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 degrees.
Input Specification
The first line of input contains an integer , the number of points.
Each of the following lines contains the coordinates of one point, two integers separated by a space. The coordinates will be between and .
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
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