import Control.Monad

main :: IO ()
main = do
    l <- words <$> getLine :: IO [String]
    let (w,h,c) = let [l1,l2,l3] = l
                   in (read l1, read l2, head l3) :: (Int,Int,Char)
    let x = if c == 'B' then 1 else 0
    forM_ [1..h] $ \i -> do
        forM_ [1..w] $ \j -> do
            putChar $ if (i+j) `rem` 2 == x then 'W' else 'B'
        putStrLn ""