W,H,C = input().split()
W,H = int(W),int(H)
if C == 'W':
    D = 'B'
else:
    D = 'W'
ans = [['-'] * W for _ in range(H)]
for i in range(H):
    for j in range(W):
        if (i + j) % 2 == 0:
            ans[i][j] = C
        else:
            ans[i][j] = D
for i in range(H):
    print(''.join(ans[i]))