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F. Disjoint Triangles
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

A point belongs to a triangle if it lies inside the triangle or on one of its sides. Two triangles are disjoint if there is no point on the plane that belongs to both triangles.

You are given $n$ points on the plane. No two points coincide and no three points are collinear.

Find the number of different ways to choose two disjoint triangles with vertices in the given points. Two ways which differ only in order of triangles or in order of vertices inside triangles are considered equal.

Input

The first line of the input contains an integer $n$ ($6 \le n \le 2000$) – the number of points.

Each of the next $n$ lines contains two integers $x_i$ and $y_i$ ($|x_i|, |y_i| \le 10^9$) – the coordinates of a point.

No two points coincide and no three points are collinear.

Output

Print one integer – the number of ways to choose two disjoint triangles.

Examples
Input
61 12 24 64 57 25 3
Output
6
Input
70 -1000000000-5 -55 -5-5 05 0-2 22 2
Output
21
Note

In the first example there are six pairs of disjoint triangles, they are shown on the picture below.

All other pairs of triangles are not disjoint, for example the following pair: