a  
 c 
 b 
 d 
 c 
 b 
 c 
 d 
 b 
 a 
 b 
 b 
 d 
 d 
 a 
 c 
 b 
 a 
 d 
 b 
 b 
 c 
 d 
 a 
 c 
 d 
 d 
 a 
 d 
 d 
 a 
 a 
 b 
 d 
 a