# coding: utf-8
# yukicoder No.82 市松模様

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

if C == "B":
    ichimatsu = ["B","W"]
else:
    ichimatsu = ["W","B"]

for i in range(H):
    for j in range(W):
        print(ichimatsu[(i + j) % 2], end = "")
    print()