W, H, C = input().split()
W = int(W)
H = int(H)
oe = [C, "B" if C=="W" else "W"]
ans = [[None]*W for _ in range(H)]
for h in range(H):
    for w in range(W):
        ans[h][w] = oe[(h+w)&1]

for a in ans:
    print(*a, sep="")