Problem:
Score : 100 points

Problem Statement

There are S sheep and W wolves.

If the number of wolves is greater than or equal to that of sheep, the wolves will attack the sheep.

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Constraints

1 \leq S \leq 100

1 \leq W \leq 100

Input

Input is given from Standard Input in the following format:

S W

Output

If the wolves will attack the sheep, print unsafe; otherwise, print safe.

Sample Input 1

4 5

Sample Output 1

unsafe

There are four sheep and five wolves. The number of wolves is not less than that of sheep, so they will attack them.

Sample Input 2

100 2

Sample Output 2

safe

Many a sheep drive away two wolves.

Sample Input 3

10 10

Sample Output 3

unsafe

Solution in Haskell (GHC 8.8.3) (judge verdict: Accepted)

import           Control.Monad.ST
import qualified Data.ByteString.Char8        as B
import qualified Data.Vector.Unboxed          as U
import qualified Data.Vector.Algorithms.Radix as U

main :: IO ()
main = do
  [s, w]  <- readInts
  putStrLn $ solve s w

solve :: Int -> Int -> String
solve s w = if w >= s then "unsafe" else "safe"

readInts :: IO [Int]
readInts = map read . words <$> getLine

readIntN :: Int ->  IO (U.Vector Int)
readIntN n = U.unfoldrN n (B.readInt . B.dropWhile ((==) ' ')) <$> B.getLine

radixSort :: U.Vector Int -> U.Vector Int
radixSort xs = runST $ do
  mxs <- U.thaw xs
  U.sort mxs
  U.freeze mxs