| 
                 
                    Closing price on 12/7/2017
                 
             | 
            
                                
             | 
         
         
 
    
        
                      
                
                    | Open | 
                    9.00 | 
                 
                
                    | High | 
                    9.00 | 
                 
                
                    | Low | 
                    8.50 | 
                     
                
                    | Volume | 
                    1,092,000 | 
                                 
                
                    | Split-adjusted Price | 
                    5.80 | 
                 
             
            
            
                
             
         | 
        
            
            
             
                            
         | 
     
 
MST Historical Quote 
        
            
                | 
                    Date
                 | 
                
                    Change
                 |                 
                
                    Open
                 |          
                
                    High
                 |            
                
                    Low
                 |                                                 
                
                    Close
                 | 
                
                    Average
                 | 
                
                    Adjusted Close
                 |                                                 
                
                    Volume
                 |     
                
                     
                 |                                       
                             
    
        			
            | 
                12/7/2017
             | 
            
                -0.90 / -9.57%
             |             
            
                9.00
             |           
            
                9.00
             |               
            
                8.50
             |                           
            
                8.50
             | 
            
                8.51
             |                     
            
                5.80
             |                                 
            
                1,092,000
             |            
            
                 
             |                                       
         
    
        
            | 
                12/6/2017
             | 
            
                0.00 / 0.00%
             |             
            
                8.50
             |           
            
                9.40
             |               
            
                8.50
             |                           
            
                9.40
             | 
            
                8.51
             |                     
            
                6.41
             |                                 
            
                4,822,100
             |  
            
                 
             |                                                              
             
    
        			
            | 
                12/5/2017
             | 
            
                -1.00 / -9.62%
             |             
            
                9.40
             |           
            
                9.40
             |               
            
                9.40
             |                           
            
                9.40
             | 
            
                9.40
             |                     
            
                6.41
             |                                 
            
                918,300
             |            
            
                 
             |                                       
         
    
        
            | 
                12/4/2017
             | 
            
                -1.10 / -9.57%
             |             
            
                11.20
             |           
            
                11.50
             |               
            
                10.40
             |                           
            
                10.40
             | 
            
                10.48
             |                     
            
                7.09
             |                                 
            
                169,400
             |  
            
                 
             |                                                              
             
    
        			
            | 
                12/1/2017
             | 
            
                -0.90 / -7.26%
             |             
            
                12.60
             |           
            
                12.60
             |               
            
                11.50
             |                           
            
                11.50
             | 
            
                12.23
             |                     
            
                7.85
             |                                 
            
                332,400
             |            
            
                 
             |                                       
         
    
        
            | 
                11/30/2017
             | 
            
                -0.60 / -4.62%
             |             
            
                13.00
             |           
            
                13.00
             |               
            
                12.40
             |                           
            
                12.40
             | 
            
                12.71
             |                     
            
                8.46
             |                                 
            
                559,700
             |  
            
                 
             |                                                              
             
    
        			
            | 
                11/29/2017
             | 
            
                -0.40 / -2.99%
             |             
            
                13.40
             |           
            
                13.40
             |               
            
                12.50
             |                           
            
                13.00
             | 
            
                12.99
             |                     
            
                8.87
             |                                 
            
                573,000
             |            
            
                 
             |                                       
         
    
        
            | 
                11/28/2017
             | 
            
                -0.50 / -3.60%
             |             
            
                13.80
             |           
            
                13.90
             |               
            
                12.70
             |                           
            
                13.40
             | 
            
                13.28
             |                     
            
                9.14
             |                                 
            
                378,600
             |  
            
                 
             |                                                              
             
    
        			
            | 
                11/27/2017
             | 
            
                +0.20 / +1.46%
             |             
            
                13.90
             |           
            
                14.00
             |               
            
                13.00
             |                           
            
                13.90
             | 
            
                13.63
             |                     
            
                9.48
             |                                 
            
                1,080,400
             |            
            
                 
             |                                       
         
    
        
            | 
                11/24/2017
             | 
            
                +1.10 / +8.73%
             |             
            
                12.50
             |           
            
                13.80
             |               
            
                11.40
             |                           
            
                13.70
             | 
            
                12.56
             |                     
            
                9.35
             |                                 
            
                352,700
             |  
            
                 
             |                                                              
             
    
        			
            | 
                11/23/2017
             | 
            
                -1.30 / -9.35%
             |             
            
                14.20
             |           
            
                14.20
             |               
            
                12.60
             |                           
            
                12.60
             | 
            
                13.13
             |                     
            
                8.60
             |                                 
            
                358,600
             |            
            
                 
             |                                       
         
    
        
            | 
                11/22/2017
             | 
            
                -0.30 / -2.11%
             |             
            
                14.10
             |           
            
                14.20
             |               
            
                13.80
             |                           
            
                13.90
             | 
            
                13.95
             |                     
            
                9.48
             |                                 
            
                142,800
             |  
            
                 
             |                                                              
             
    
        			
            | 
                11/21/2017
             | 
            
                -0.10 / -0.70%
             |             
            
                14.30
             |           
            
                14.30
             |               
            
                14.20
             |                           
            
                14.20
             | 
            
                14.23
             |                     
            
                9.69
             |                                 
            
                257,000
             |            
            
                 
             |                                       
         
    
        
            | 
                11/20/2017
             | 
            
                +0.20 / +1.42%
             |             
            
                14.10
             |           
            
                14.50
             |               
            
                14.10
             |                           
            
                14.30
             | 
            
                14.30
             |                     
            
                9.76
             |                                 
            
                167,400
             |  
            
                 
             |                                                              
             
    
        			
            | 
                11/17/2017
             | 
            
                -0.60 / -4.08%
             |             
            
                14.90
             |           
            
                14.90
             |               
            
                14.00
             |                           
            
                14.10
             | 
            
                14.33
             |                     
            
                9.62
             |                                 
            
                414,700
             |            
            
                 
             |                                       
         
    
        
            | 
                11/16/2017
             | 
            
                0.00 / 0.00%
             |             
            
                14.70
             |           
            
                14.80
             |               
            
                14.60
             |                           
            
                14.70
             | 
            
                14.71
             |                     
            
                10.03
             |                                 
            
                518,500
             |  
            
                 
             |                                                              
             
    
        			
            | 
                11/15/2017
             | 
            
                0.00 / 0.00%
             |             
            
                14.70
             |           
            
                14.80
             |               
            
                14.40
             |                           
            
                14.70
             | 
            
                14.55
             |                     
            
                10.03
             |                                 
            
                399,800
             |            
            
                 
             |                                       
         
    
        
            | 
                11/14/2017
             | 
            
                +0.50 / +3.52%
             |             
            
                14.20
             |           
            
                14.70
             |               
            
                14.20
             |                           
            
                14.70
             | 
            
                14.53
             |                     
            
                10.03
             |                                 
            
                546,500
             |  
            
                 
             |                                                              
             
    
        			
            | 
                11/13/2017
             | 
            
                -0.20 / -1.39%
             |             
            
                14.40
             |           
            
                14.60
             |               
            
                14.20
             |                           
            
                14.20
             | 
            
                14.36
             |                     
            
                9.69
             |                                 
            
                197,900
             |            
            
                 
             |                                       
         
    
        
            | 
                11/10/2017
             | 
            
                -0.10 / -0.69%
             |             
            
                14.60
             |           
            
                14.80
             |               
            
                14.30
             |                           
            
                14.40
             | 
            
                14.60
             |                     
            
                9.82
             |                                 
            
                447,500
             |  
            
                 
             |                                                              
             
    
        			
            | 
                11/9/2017
             | 
            
                -0.20 / -1.36%
             |             
            
                14.80
             |           
            
                14.90
             |               
            
                14.50
             |                           
            
                14.50
             | 
            
                14.67
             |                     
            
                9.89
             |                                 
            
                211,600
             |            
            
                 
             |                                       
         
    
        
            | 
                11/8/2017
             | 
            
                +0.20 / +1.38%
             |             
            
                14.50
             |           
            
                14.70
             |               
            
                14.30
             |                           
            
                14.70
             | 
            
                14.41
             |                     
            
                10.03
             |                                 
            
                377,500
             |  
            
                 
             |                                                              
             
    
        			
            | 
                11/7/2017
             | 
            
                -0.20 / -1.36%
             |             
            
                14.60
             |           
            
                14.80
             |               
            
                14.50
             |                           
            
                14.50
             | 
            
                14.62
             |                     
            
                9.89
             |                                 
            
                593,000
             |            
            
                 
             |                                       
         
    
        
            | 
                11/6/2017
             | 
            
                -0.10 / -0.68%
             |             
            
                14.80
             |           
            
                15.00
             |               
            
                14.70
             |                           
            
                14.70
             | 
            
                14.87
             |                     
            
                10.03
             |                                 
            
                121,400
             |  
            
                 
             |                                                              
             
    
        			
            | 
                11/3/2017
             | 
            
                -0.30 / -1.99%
             |             
            
                15.10
             |           
            
                15.20
             |               
            
                14.80
             |                           
            
                14.80
             | 
            
                14.98
             |                     
            
                10.10
             |                                 
            
                636,900
             |            
            
                 
             |                                       
         
    
        
            | 
                11/2/2017
             | 
            
                +0.60 / +4.14%
             |             
            
                14.60
             |           
            
                15.10
             |               
            
                14.50
             |                           
            
                15.10
             | 
            
                14.73
             |                     
            
                10.30
             |                                 
            
                667,100
             |  
            
                 
             |                                                              
             
    
        			
            | 
                11/1/2017
             | 
            
                +0.70 / +5.07%
             |             
            
                13.90
             |           
            
                14.50
             |               
            
                13.80
             |                           
            
                14.50
             | 
            
                14.18
             |                     
            
                9.89
             |                                 
            
                910,300
             |            
            
                 
             |                                       
         
    
        
            | 
                10/31/2017
             | 
            
                -0.10 / -0.72%
             |             
            
                13.80
             |           
            
                14.10
             |               
            
                13.80
             |                           
            
                13.80
             | 
            
                13.96
             |                     
            
                9.41
             |                                 
            
                800,200
             |  
            
                 
             |                                                              
             
    
        			
            | 
                10/30/2017
             | 
            
                +0.60 / +4.51%
             |             
            
                13.50
             |           
            
                14.00
             |               
            
                13.50
             |                           
            
                13.90
             | 
            
                13.75
             |                     
            
                9.48
             |                                 
            
                474,100
             |            
            
                 
             |                                       
         
    
        
            | 
                10/27/2017
             | 
            
                -0.10 / -0.75%
             |             
            
                13.50
             |           
            
                13.50
             |               
            
                13.10
             |                           
            
                13.30
             | 
            
                13.22
             |                     
            
                9.07
             |                                 
            
                119,300
             |  
            
                 
             |                                                              
             
    
         
    
    
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