main = getLine >>= mapM_ putStrLn . solve . words

solve :: [String] -> [String]
solve [w, h, c] = take (read h) ys
	where
	(x : xs) = cycle $ if c == "B" then "BW" else "WB"
	a = take (read w) $ x : xs
	b = take (read w) $ xs
	ys = cycle [a, b]