B B B B B B B B B A A A A A A A A A B B B B B B B B 
B A A A A A A A A A A B B B B B B B B B A A A A A A 
A A A B B B B B B B B B B A A A A A A A A A B B B B 
B B B B B A A A A A A A A A A B B B B B 
done with B 
A A A A 
done with A 
C C 
C C C C C C C C C C C C C C C C C C C C C C C C C C 
C C C C C C C C C C C C C C C C C C C C C C C 
done with C 
