Given n points in the plane that are all pairwise distinct, a “boomerang” is a tuple of points (i, j, k) such that the distance between i and j equals the distance between i and k (the order of the tuple matters).

Find the number of boomerangs. You may assume that n will be at most 500 and coordinates of points are all in the range [-10000, 10000] (inclusive).

给定平面中的n个点都是成对不同的，“回旋镖”是点（i，j，k）的元组，使得i和j之间的距离等于i和k之间的距离（元组的顺序很重要））。

找到飞去来器的数量。 您可以假设n最多为500，点的坐标都在[-10000,10000]（含）范围内。

Example:

Input:
[[0,0],[1,0],[2,0]]

Output:
2

Explanation:
The two boomerangs回力镖 are [[1,0],[0,0],[2,0]] and [[1,0],[2,0],[0,0]]