def DRAWING(W, H, C):
    pattern = []
    for i in range(H):
        row = []
        for j in range(W):
            if (i + j) % 2 == 0:
                row.append(C)
            else:
                row.append('B' if C == 'W' else 'W')
        pattern.append(''.join(row))
    return '\n'.join(pattern)
INPUT = input().split()
W, H, C = int(INPUT[0]), int(INPUT[1]), INPUT[2]
print(DRAWING(W, H, C))