import sys
from sys import stdin
import math
import heapq

N = int(stdin.readline())

XY = []

for i in range(N):

    X,Y = map(int,stdin.readline().split())
    XY.append((X,Y))

ans = 0

for i in range(N):

    x,y = XY[i]
    s = set()

    for j in range(N):
        
        if j == i:
            continue
        x2,y2 = XY[j]

        xx = x2 - x
        yy = y2 - y

        g = math.gcd(xx,yy)
        xx //= g
        yy //= g

        if (xx,yy) in s:
            ans += 1
            break
        s.add((xx,yy))

print (ans)