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

int main(int argc, char *argv[])
{ 
    int n; long double total;
    cout << "Please enter a number" << endl;
    cin >> n;
    cout << "\n\n";
    total=0.0;
    for(int i=1; i<=n; i++){
       total+=1.0/(i*i);    
    }
    total=6.0*total;
    total=sqrt(total);
    cout << "Pi calculates out to: " << total << "\n\n" << endl;
    system("pause");
}