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

if C == "B":
    other = "W"
else:
    other = "B"

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