...

#include<bits/stdc++.h>
using namespace std;
int sushu(int x){
if(x == 1) return false;
for(int i = 2;i * i <= x;i++) if(x % 2 == 0) return false;
return true;
}
int main(){
int n;
cin >> n;
if(sushu(n)) cout << "Yes";
else cout << "No";
return 0;
}