UVA 10490 Mr. Azad and his Son!!!!!

/***
Md. Nazmul Hasan
Shahjalal University of Science & Technology,Sylhet.
hasan08sust@gmail.com
***/
#include<iostream>
#include<cstdio>
#include<stack>
#include<queue>
#include<map>
#include<vector>
#include<algorithm>
#include<cstring>
#include<sstream>
#include<cmath>
#include <iomanip>
using namespace std ;
typedef long long ll ;
typedef int in ;
typedef unsigned long long ull ;
const double pi = 2*acos(0) ;
#define maxi 40000
#define pf printf
#define sc scanf
#define pb push_back
#define MEM(x,y) (memset((x),(y),sizeof(x)))
#define MIN(x,y) ((x) < (y) ? (x) : (y))
#define MAX(x,y) ((x) > (y) ? (x) : (y))
#define load(array,size)  for(int i=0 ; i<size ; i++) cin>>array[i]  ;
#define new_line  pf("\n")
#define clear_data(array) memset(array,0,sizeof(array))
#define highest_int 2147483647


int main()
{
    int n,cnt;
    long long int m;
    int prime[] = {2,3,5,7,11,13,17,19,23,29,31};

    while(sc("%d",&n) &&n)
    {
        cnt=0;

        for(int i=0 ; i<11 ; i++)
        {
            if(n==prime[i])
                cnt=1;
        }


        if(cnt==1)
        {
            if(n==11 || n==23 || n==29)
            {
                pf("Given number is prime. But, NO perfect number is available.\n");
            }
            else
            {
                m = pow(2,n-1)*(pow(2,n)-1);
                pf("Perfect: %lld!\n",m);
            }
        }
        else
        {
            pf("Given number is NOT prime! NO perfect number is available.\n");
        }

    }

    return 0;
}