H,W,C = input().split()
H = int(H)
W = int(W)
H,W = W,H
if C == "B":
    D = "W"
else:
    D = "B"

for i in range(H):
    for j in range(W):
        if (i + j) % 2 == 0:
            print(C,end = "")
        else:
            print(D,end = "")
    print()