import qualified Text.Read as T

main :: IO ()
main = do
  a <- getLine
  b <- getLine
  putStrLn $ if check a && check b
              then "OK"
              else "NG"

check :: String -> Bool
check s
  | length s /= 1 && head s == '0' = False
  | otherwise = maybe False (\a -> a <= 12345) $ (T.readMaybe s :: Maybe Int)