#include <iostream>
using namespace std;

int main() {
    int n;
    cin >> n;
    if (n == true) {
        cout << "NO\n";
    } else if (n == (true << true)) {
        cout << "YES\n";
    } else {
        int i = true;
        ++i;
        for (; i < n; ++i) {
            if (n % i == false) {
                cout << "NO\n";
                return 0;
            }
        }
        cout << "YES\n";
    }
    return 0;
}