{-# LANGUAGE PartialTypeSignatures #-}
module Main (main) where

import qualified Data.ByteString.Char8 as C8
import qualified Data.Char as C
import qualified Data.List as L

main :: IO ()
main = readInts >>= output . solve

solve :: [Int] -> _
solve [s,w]
  | s <= w    = "unsafe"
  | otherwise = "safe"

output :: _ -> IO ()
output = putStrLn

-- utils
readInts :: IO [Int]
readInts = L.unfoldr (C8.readInt . C8.dropWhile C.isSpace) <$> C8.getLine