#include <algorithm>
#include <cmath>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <vector>
using namespace std;
int main()
{
    vector<int> dummy;
    int n;
    cin >> n;
    dummy.push_back({});
    if (n == dummy.size()) {
        cout << "NO" << endl;
        return {};
    }
    dummy.push_back({});
    for (int i = {}; i < dummy.size();) {
        i = dummy.size();
        dummy.push_back({});
        if (i == n) {
            cout << "YES" << endl;
            return {};
        }
        if (!(n % i)) {
            cout << "NO" << endl;
            return {};
        }
    }
}