#include <iostream>

#include <iostream>
using namespace std;
int main(){
int n,i;
cin >> n;
bool a;
if(n == 2){
a = true;
}else{
for(i = 2; i <= n - 1; i++){
if(n % i == 0){
a = false;
break;
}
}
if(i == n){
a = true;
}
}
if(a == true){
cout << "Yes";
}else{
cout << "No";
}
return 0;
}