Div 1 Problem J

/*-----------------------------------------*/
//Author      : Mir Riyanul Islam (Riyan)
//University  : AIUB
//E-mail      : [email protected]
//Problem ID  : 10310
//Problem Name: Dog and Gopher
//Algorithm   : Geometry
/*-----------------------------------------*/
#pragma warning (disable : 4786)
#pragma comment(linker, "/STACK:16777216")
#include <set>
#include <map>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iostream>
#include <algorithm>

using namespace std;



const double EPS = 1e-11;
const int INF = ( 1<<29 );
const double PI = 2 * acos( 0.0 );

int MAX( int a , int b ) { return a > b ? a : b;  }
int MIN( int a , int b ) { return a < b ? a : b;  }
void SWAP( int &a , int &b ) { int t = a; a = b; b = t; }
int GCD( int a , int b ) { while( b ) { b ^= a ^= b ^= a %= b; } return a; }

int main() {
    freopen( "input.txt" , "r" , stdin );
    freopen( "output.txt" , "w" , stdout );
    int tc , cn = 0;
    double r;
    scanf( "%d" , &tc );
    while( tc-- ) {
        scanf( "%lf" , &r );
        printf( "Case %d: %.2lf\n" , ++cn , ( r * r ) * ( PI - ( sqrt( 3.0 ) / 2.0 ) ) );
    }
    return 0;
}