n=int(input())
p=[tuple(map(int,input().split())) for i in range(n)]
a=0
from math import gcd
for i in range(n):
  sx,sy=p[i]
  d={}
  for j in range(n):
    if i==j:
      continue
    tx,ty=p[j]
    dx,dy=tx-sx,ty-sy
    if dx==0:
      v=(0,dy//abs(dy))
    elif dy==0:
      v=(dx//abs(dx),0)
    else:
      g=gcd(abs(dx),abs(dy))
      v=(dx//g,dy//g)
    if v not in d:
      d[v]=0
    d[v]+=1
  a+=any(d[v]>=2 for v in d)
print(a)