import Data.List ( intersperse )

splitEveryN :: Int -> [a] -> [[a]]
splitEveryN n = takeWhile (not . null) . map (take n) . iterate (drop n)

myCeiling :: Int -> Int -> Int
myCeiling a b = ceiling $ fromIntegral a / fromIntegral b

map2 :: (a -> a) -> [a] -> [a]
map2 _ []       = []
map2 _ [x]      = [x]
map2 f (x:y:zs) = (x : (f y) : (map2 f zs))

next :: Char -> Char
next 'W' = 'B'
next 'B' = 'W'


solve :: Int -> Int -> Char -> [String]
solve w h c
    | odd w && odd h  = map2 reverse $ splitEveryN w $ (++ [c]) $ concat $ replicate d ([c] ++ [next c])
    | otherwise = map2 reverse $ splitEveryN w $ concat $ replicate d ([c] ++ [next c])
    where
        d = (w * h) `div` 2
        e = myCeiling (w + h) 2

main :: IO ()
main = do
    [a, b, s] <- words <$> getLine
    let w   = (read :: String -> Int) a
        h   = (read :: String -> Int) b
        [c] = s
        z   = solve w h c 
    putStr $ unlines z