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
Input Specification
The first line of input contains an integer
Each of the following
No two points will be located at the same coordinates.
Output Specification
Output the number of right triangles.
Sample Input 1
Copy
3
4 2
2 1
1 3
Sample Output 1
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1
Sample Input 2
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4
5 0
2 6
8 6
5 7
Sample Output 2
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0
Sample Input 3
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5
-1 1
-1 0
0 0
1 0
1 1
Sample Output 3
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7
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