1381 : A MST Problem

It is just a mining spanning tree ( 最小生成树 ) problem, what makes you a little difficult is that you are in a 3D space.

The first line of the input contains the number of test cases in the file. And t he first line of each case
contains one integer numbers n(0<n<30) specifying the number of the point . The n next n line s, each line
contain s Three Integer Numbers xi,yi and zi, indicating the position of point i.

For each test case, output a line with the answer, which should accurately rounded to two decimals .

2
2
1 1 0
2 2 0
3
1 2 3
0 0 0
1 1 1

1.41
3.97