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

n=int(input())
c=[]
for x in range(n):
	c.append([int(x) for x in input().split()])
co=0
for z in list(itertools.combinations(c,3)):
	d=[]
	for v in list(itertools.combinations(z,2)):
		xi,yi=v[0]
		x,y=v[1]
		m=(xi-x)/(yi-y) if (yi-y)!=0 else "v"
		if not m in d:
			d.append(m)
	if(len(d)==3):
		co+=1
print(co)