isPrime 1 = False
isPrime n = helper n 2
  where
    helper n x
      | x * x > n = True
      | n `mod` x == 0 = False
      | otherwise = helper n (x+1)
                    
main = do
  n <- readLn
  putStrLn $ if n == 1 || isPrime n then "NO" else "YES"