2324: Profit

Liu Sir has cut the cake into pieces,and now he will give them to the BUCT ACMers.However,the ACMers stay in different positions.So Liu wants to find a point where ACMers can take the total distance shortest to get the cakes.
To make it easy,Liu makes a coordinate,and now the positions of every ACMer(xi,yi) are given.The point he wants to choose is at  the X-ray.But He didn't knows which is the best.Can you help him?
No ACMer is at the X-ray.

 First Line is a number T,indicating that there are T cases.
    In each case,there is a N in the first line,indicating there are N ACMers.Then in the following N lines ,each line has two number xi yi,indicating the postion of  the ith ACMer.(0.00<xi,yi<100.00,0<N<1000)

For each test case,output "Case X: Z"in a line.Z is the position Liu Sir wants to find.

1
3
1.00 1.00
2.00 2.00
3.00 3.00

Case 1: 1.67879