from math import gcd

N = int(input())
XY = [list(map(int, input().split())) for _ in range(N)]

def vec(a, b):
    return (b[0]-a[0], b[1]-a[1])

ans = 0
for X, Y in XY:
    S = set()
    for X1, Y1 in XY:
        if (X, Y) == (X1, Y1): continue
        a, b = vec((X, Y), (X1, Y1))
        GCD = gcd(abs(a), abs(b))
        a //= GCD
        b //= GCD
        if (a, b) in S:
            ans += 1
            break
        S.add((a, b))

print(ans)