~N~ points are placed in the coordinate plane.

Write a program which calculates in how many ways a right triangle can be formed by three of the given points. A right triangle is one in which one of the angles is ~90~ degrees.

Input Specification

The first line of input contains an integer ~N~ ~(3 \le N \le 1500)~, the number of points.

Each of the following ~N~ lines contains the coordinates of one point, two integers separated by a space. The coordinates will be between ~-10^9~ and ~10^9~.

No two points will be located at the same coordinates.

Output Specification

Output the number of right triangles.

Sample Input 1

3
4 2
2 1
1 3

Sample Output 1

1

Sample Input 2

4
5 0
2 6
8 6
5 7

Sample Output 2

0

Sample Input 3

5
-1 1
-1 0
0 0
1 0
1 1

Sample Output 3

7