W, H, C = input().split()

if C == 'B':
    
    D = 'W'
    
else:
    
    D = 'B'
    
    
for i in range(int(H)):
    
    for j in range(int(W)):
        
        if (i + j) % 2:
            
            print(D, end='')
            
        else:
            
            print(C, end='')
            
    print()