prime numbers 

#include <iostream>
using namespace std;

int main() {
    int n, i =1;
    
    cin>>n;
    int factor = 0;
    while(i<=n){
        if(n%i==0){
            factor++;
        }
        i++;
    }
    if(factor==2){
        cout<<"it is a prime number";
    }
    
    else{
        cout<<"not a prime number";
    }
    return 0;
}