#include <iostream>
#include <cstdint>

using namespace std;

int main() {

  ios::sync_with_stdio(false);
  cin.tie(0);

  int64_t n;
  cin >> n;
  bool sosuu;
  if (n == 1) {
    cout << "NO" << endl;
    return 0;
  }
  for (int i = 2; i * i <= n; i++) {
    if (n % i == 0) {
      sosuu = false;
      break;
    } else {
      sosuu = true;
    }
  }
  cout << (sosuu ? "NO" : "YES") << endl;
}