Untitled

#include <iostream>
using namespace std;
int main()
{
int num;
bool prime = true;
cin >> num;
if(num <= 1){
    prime = false;
}
else {
    for(int i = 2; i * i <= num; ++i){
        if(num % i == 0){
            prime = false;
        }
    }
}
if(prime){
    cout << "YES";
}else {
cout << "NO";
}
}

}