#include <vector>
#include <iostream>
using namespace std;

int main(void){
    bool ans=true;
    int n;
    cin>>n;
    vector<bool>v;
    v.push_back(true);
    v.push_back(true);
    if(n==ans)ans=false;
    while(v.size()<n){
        if(!(n%v.size()))ans=false;
        v.push_back(true);
    }
    cout<<(ans==true?"YES":"NO")<<endl;
}