题目描述

Given a set of points with integer coordinates xi, yi, i = 1...N, your program must find all the squares having each of four vertices in one of these points.

输入要求

Input file contains integer N followed by N pairs of integers xi yi.
Constraints

-10^4 ≤ xi, yi ≤ 10^4, 1 ≤ N ≤ 2000. All points in the input are different.

输出要求

Output file must contain a single integer ― number of squares found.

输入样例

4
1 0
0 1
1 1
0 0
4
-2 5
3 7
0 0
5 2

输出样例

1
1

提示

来源