f ('0':_:_) = True
f xs    | foldr p False xs  = True
        | otherwise         = if read xs > 12345 then True else False
        where
            p x y = any (==x) moji || y
            moji = ['a'..'z'] ++ ['A'..'Z']

solve as bs
    | f as || f bs  = "NG"
    | otherwise     = "OK"

main = do
    as <- getLine
    bs <- getLine
    putStrLn $ solve as bs