Problem H

Statement
Copy Copied
Description:
You are given a set of $$$n$$$ points in a 2D plane. No three points are collinear.

A pentagram is a set of $$$5$$$ points $$$A,B,C,D,E$$$ that can be arranged as follows.  Note the length of the line segments don't matter, only that those particular intersections exist.

Count the number of ways to choose $$$5$$$ points from the given set that form a pentagram.

Input Format:
The first line contains an integer $$$n$$$ ($$$5 \leq n \leq 300$$$) — the number of points.

Each of the next $$$n$$$ lines contains two integers $$$x_i, y_i$$$ ($$$-10^6 \leq x_i,y_i \leq 10^6$$$) — the coordinates of the $$$i$$$-th point. It is guaranteed that no three points are collinear.

Output Format:
Print a single integer, the number of sets of $$$5$$$ points that form a pentagram.

Note:
A picture of the first sample:  A picture of the second sample:  A picture of the third sample: