def main():
    W, H, C = input().split()

    w = int(W)
    h = int(H)
    if C == 'B':
        a = 'BW' * 26
    else:
        a = 'WB' * 26

    for i in range(h):
        if not i % 2:
            print(a[0:w])
        else:
            print(a[1:w+1])

main()