Untitled

#include <iostream>
using namespace std;
int main(){
    long long n;cin>>n;int v=0;

   for (int i = 2;i<n;++i) {
            if (n % i == 0)
                v++;
            if (v)
            {
                cout<<"NO";
                return 0;
            }
     }
    cout<<"YES";
    
return 0;
}