import Data.Maybe
import qualified Data.ByteString.Char8 as B

getInts = map f . B.words <$> B.getLine
    where f = fst . fromJust . B.readInteger

solve h w d = [[f x y | x <- [1..w]] | y <- [1..h]]
    where
    f x y = c u v
        where
        g z = (z `mod` (2*d)) `div` d
        u = g (x+y)
        v = g (x-y)
        c 0 0 = 'R'
        c 0 1 = 'G'
        c 1 0 = 'B'
        c 1 1 = 'Y'
        c _ _ = 'X'

main = do
    [h, w, d] <- getInts
    mapM_ putStrLn $ solve h w d
