import           Control.Monad.State
import qualified Data.ByteString.Char8        as B

type Parser a = StateT B.ByteString Maybe a

parseInt :: Parser Int
parseInt = StateT $ B.readInt . B.dropWhile ((==) ' ')

readParser :: Parser a -> IO a
readParser p = maybe (error "parser error") fst . runStateT p <$> B.getLine

main :: IO ()
main = do
  (s, w) <- readParser $ (,) <$> parseInt <*> parseInt
  putStrLn $ solve s w

solve :: Int -> Int -> String
solve s w
  | w >= s    = "unsafe"
  | otherwise = "safe"
