import sys
import math
input = sys.stdin.readline
def read_values(): return map(int, input().split())
def read_index(): return map(lambda x: int(x) - 1, input().split())
def read_list(): return list(read_values())
def read_lists(N): return [read_list() for _ in range(N)]

def main():
    n=int(input())
    x=[0]*n
    y=[0]*n
    for i in range(n):
        x[i],y[i]=read_values()
    mp=dict()
    for i in range(n):
        for j in range(n):
            if i==j:continue
            dx=y[i]-y[j]
            dy=-x[i]+x[j]
            dc=-(dx*x[i]+dy*y[i])
            g=math.gcd(dx,dy,dc)
            if dx<0 or (dx==0 and dy<0):
                g*=-1
            if g==0:
                continue
            dx//=g
            dy//=g
            dc//=g
            ad=(dx,dy,dc)
            if not ad in mp:
                mp[ad]=set()
            mp[ad].add(i)
    uh=[0]*n
    for vc in mp.values():
        if len(vc) < 3:
            continue
        if len(vc) > 3:
            for v in vc:
                uh[v]|=1
            continue
        vl=list(vc)
        for i in range(3):
            inner = (x[vl[(i+2)%3]]-x[vl[i]])*(x[vl[(i+1)%3]]-x[vl[i]])+(y[vl[(i+2)%3]]-y[vl[i]])*(y[vl[(i+1)%3]]-y[vl[i]])
            if inner > 0:
                uh[vl[i]]|=1
    print(sum(uh))

if __name__ == "__main__":
    main()