W,H,C=input().split()
W,H=int(W),int(H)
if C=='B':
    C = 0
else:
    C = 1

for i in range(H):
    for j in range(W):
        if (i+j+C)%2==0:
            print('B',end='')
        else:
            print('W',end='')
    print()