UVa - 10490 - Mr. Azad and his Son!!!!!

#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
using namespace std;

int main(){
    int n;
    while(cin >> n){
        if(n == 0)break;
        int prove = 0;
        for(int i = 2; i <= sqrt(n); i++)
            if(n%i == 0){
                prove = 1;break;
            }
    if(prove == 0){
        if(n == 2)cout << "Perfect: 6!" << endl;
        else if(n == 3)cout << "Perfect: 28!" << endl;
        else if(n == 5)cout << "Perfect: 496!" << endl;
        else if(n == 7)cout << "Perfect: 8128!" << endl;
        else if(n == 13)cout << "Perfect: 33550336!" << endl;
        else if(n == 17)cout << "Perfect: 8589869056!" << endl;
        else if(n == 19)cout << "Perfect: 137438691328!" << endl;
        else if(n == 31)cout << "Perfect: 2305843008139952128!" << endl;
        else cout << "Given number is prime. But, NO perfect number is available." << endl;
    }
    else cout << "Given number is NOT prime! NO perfect number is available." << endl;
    }

    return 0;
}