#include <iostream>

#include <cstdio>

#include <cstring>

#include <map>

#include <algorithm>

#include <queue>

#include <cmath>

#include <stack>

#include <set>

using namespace std;

int main(){

    int T;

    scanf("%d",&T);

    for(int cas=;cas<=T;cas++){

        int a[];

        for(int i=;i<;i++)

            scanf("%d",&a[i]);

        sort(a,a+);

        printf("Case %d: ",cas);

        if(a[]<(a[]+a[]+a[])){

            double p=(a[]+a[]+a[]+a[])/2.0;

            printf("%.6lf\n",sqrt((p-a[])*(p-a[])*(p-a[])*(p-a[])));

        }

        else puts("-1");

    }

    return ;

}