import math
N=int(input())
p=[tuple(map(int,input().split())) for _ in range(N)]
cnt=0
for i in range(N):
    d={}
    a_x,a_y=p[i]
    for j in range(N):
        if i==j:
            continue
        d_x,d_y=p[j][0]-a_x,p[j][1]-a_y
        if d_x==0:
            d_y//=abs(d_y)
        else:
            v=math.gcd(d_x,d_y)
            d_x,d_y=d_x//v,d_y//v
        if (d_x,d_y) in d:
            cnt+=1
            break
        d[(d_x,d_y)]=1
    #print(i,d,cnt)
print(cnt)