10
-2 1
2 -2
-1 -2
0 0
2 -1
0 -2
2 2
0 2
-1 -1
1 -2
 40
-8 24
2 -1
1 -18
72 -70
5 -4
-308 436
-19 40
36 -35
-178 265
-1 2
-7 30
-1 0
3 -2
200 -285
17 -16
-35 74
0 -4
-86 106
-1 4
-7 6
0 1
-5 4
-2 3
6 -5
-4 5
181 -262
76 -118
0 0
-7 18
-58 104
-5 6
-6 12
-3 4
1 0
11 -10
-86 130
-3 6
153 -236
-183 270
-33 64
 5
0 -1
0 -2
0 -3
0 -4
0 -5
 10
0 1
-1 -1
1 1
-1 0
1 -1
-2 -1
-2 2
-2 0
0 -2
0 -1
 20
-1 18
-2 5
-5 4
2 -33
9 -18
0 0
11 -22
2 0
-1 2
-4 41
1 6
1 -2
6 -12
0 1
-3 6
3 -6
3 -8
-1 4
2 -5
1 0
 10
2 1
-1 0
-2 -1
-1 1
0 2
2 -2
0 0
-2 -2
0 -2
-2 1
 20
-3 -3
0 4
-3 1
1 1
-1 2
-4 4
3 -1
-3 0
0 2
4 0
2 3
2 4
4 -3
-4 3
-1 1
1 3
-2 4
1 -2
1 -1
3 0
 3
0 0
0 -1
0 1
 10
2 1
-1 1
0 0
-3 1
-2 -3
-1 -2
-1 -1
1 2
3 -2
0 -2
 3
3 3
1 2
1 1
 4
0 0
1 0
2 0
3 0
 9
1 1
1 0
0 1
0 0
-1 0
-1 1
-1 -1
1 -1
0 -1
 7
1 1
-1 -1
1 0
0 1
-1 0
0 -1
0 0

4
 57
 4
 5
 21
 4
 10
 1
 1
 0
 2
 8
 3

from fractions import gcd

def colinear(p1, p2, p3):
	return (p2[1] - p1[1]) * (p3[0] - p2[0]) == (p3[1] - p2[1]) * (p2[0] - p1[0])

n = int(input())

pontos = []
x = []
y = []
pontosSet = set()
for i in range(0, n):
	s = input().split()
	p = (int(s[0]), int(s[1]))
	pontos.append(p)
	pontosSet.add(p)

pontos.sort()

for i in range(0, n):
	p = pontos[i]
	x.append(p[0])
	y.append(p[1])

cont = 0
for i in range(0, n):
	for j in range(i + 2, n):
		p = pontos[i]
		vetor = (x[j] - x[i], y[j] - y[i])
		div = gcd(abs(vetor[0]), abs(vetor[1]))
		vetor = (int(vetor[0] / div), int(vetor[1] / div))
		k = 1
		meio = (pontos[i][0] + k * vetor[0], pontos[i][1] + k * vetor[1])
		while (meio < pontos[j]):
			if (colinear(meio, pontos[i], pontos[j]) and meio in pontosSet):
				# print(pontos[i], meio, pontos[j])
				cont += 1
			k += 1
			meio = (pontos[i][0] + k * vetor[0], pontos[i][1] + k * vetor[1])

print(cont)
