lightoj1022

#include<iostream>
#include<cstdio>
#include<cmath>
#include<memory.h>
#include<algorithm>
using namespace std;
int main()
{
    int T;
    cin >> T;
    int u = 0;
    while (T--)
    {
        double r;
        cin >> r;
        printf("Case %d: %.2f\n", ++u, r*r*4 - 2*r*r*acos(0.0)+1e-9);
    }
    return 0;
}