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

S = 'BW' * 26
C = [0, 1][C == 'W']
for i in range(H):
    if i % 2 == 0:
        print(S[0+C:W+C])
    else:
        print(S[1+C:W+C+1])