Quadrilaterals#711
You are given points in general position on the plane, meaning no two points coincide and no three points are collinear. Determine the number of distinct convex quadrilaterals that can be formed using these points as vertices.
The first line contains a single integer (4 \leq N \leq 1500).
Each of the next lines contains two integers X_i and Y_i — the coordinates of a point. All coordinates do not exceed 10^8 in absolute value.
Output a single integer — the number of distinct convex quadrilaterals with vertices among the given points.
Example 1