def my_gcd(a, b):
    if b == 0:
        return a
    else:
        return my_gcd(b, a % b)

N = int(input())
X = []
Y = []
for i in range(N):
    x, y = map(int, input().split())
    X.append(x)
    Y.append(y)
pos = [False for _ in range(N)]
for i in range(N):
    lst = []
    st = set()
    for j in range(N):
        if i == j:
            lst.append([-1, -1])
            continue
        dx = X[j] - X[i]
        dy = Y[j] - Y[i]
        if dx == 0:
            dy = dy / abs(dy)
        elif dy == 0:
            dx = dx / abs(dx)
        else:
            g = my_gcd(max(abs(dx), abs(dy)), min(abs(dx), abs(dy)))
            dx /= g
            dy /= g
        lst.append([dx, dy])
        st.add((dx, dy))
    for j in range(N):
        if i == j:
            continue
        lst2 = (lst[j][0] * -1, lst[j][1] * -1)
        if lst2 in st:
            pos[j] = True
ans = 0
for i in range(N):
    if pos[i]:
        ans += 1
print(ans)