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.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"