Untitled

// Online C++ compiler to run C++ program online
#include <iostream>
using namespace std;

int main() {
    int n, prime = 1;
    cin >> n;
    if (n <= 1) prime = 0;
    for (int i = 2; i < n && prime == 1; i++)
        if (n % i == 0) prime = 0;
    if (prime == 1)
        cout << "yes";
    else
        cout << "no";

    return 0;
}