Vanya got bored and he painted *n* distinct points on the plane. After that he connected all the points pairwise and saw that as a result many triangles were formed with vertices in the painted points. He asks you to count the number of the formed triangles with the non-zero area.
The first line contains integer *n* (1 ≤ *n* ≤ 2000) — the number of the points painted on the plane. 

Next *n* lines contain two integers each *x*<sub class="lower-index">*i*</sub>, *y*<sub class="lower-index">*i*</sub> ( - 100 ≤ *x*<sub class="lower-index">*i*</sub>, *y*<sub class="lower-index">*i*</sub> ≤ 100) — the coordinates of the *i*-th point. It is guaranteed that no two given points coincide.
import itertools
import collections

Point = collections.namedtuple('Point', ['x', 'y'])

def isTriengle(p1, p2, p3):
	return (p1.x - p3.x) * (p2.y - p3.y) - (p2.x - p3.x) * (p1.y - p3.y)

n = int(input())
points = []
for _ in range(n):
	raw = input().split()
	points.append(Point(int(raw[0]), int(raw[1])))

triangles = 0
for comb in itertools.combinations(points, 3):
	if isTriengle(*comb):
		triangles += 1

print(triangles)
