#!/usr/bin/python
# -*- coding: utf-8 -*-

### INPUT ###
W,H,C = map(str, raw_input().split())
ans = ""
if C == "B":
	tmp = "BW" * int(W) * int(H)
else:
	tmp = "WB" * int(W) * int(H)

for i in range(int(H)):
	ans += tmp[ i * 0 + i % 2 : i * 0 + int(W) + i % 2] + "\n"

print ans.rstrip("\n")