A MST Problem

<p> 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. </p>

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

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