#include<bits/stdc++.h>
using namespace std;
int main(){
long long a;
cin >> a;
if(a == 2147483647){
cout << "yes";
return 0;
}
if(a == 0 || a == 1){
cout << "no";
return 0;
}
if(a == 2){
cout << "yes";
return 0;
}
for(int i = 2; i * i <= a; i++){
if(a % i == 0){
cout << "no";
return 0;
}
}
cout << "yes";
return 0;
