ACACACACACACACACAC

#include<iostream>
using namespace std;
bool SB(long long n){
    int flag=0;
    for(int i=1;i<=n;i++){
        if(n%i==0) flag++;
    }
    if(flag==2) return true;
    else return false;
}
int main() {

	long long n;
	cin >> n;
	if(SB(n)) cout << "Yes" << endl;
	else cout << "No" << endl;
    
   return 0;
}