#include<bits/stdc++.h>

#define ll long long
#define f first
#define s second

using namespace std;

const int N = 2506;

ll n, tx, ans, k, k1, k2, st;

map < pair <int, int>, int > sto;
map < pair <int, int>, int > :: iterator it;

pair <int, int> t, t1, t2, a[N];

int main()
{
    ios_base::sync_with_stdio(); cin.tie(); cout.tie();
    cin >> n;
    for (int i = 1; i <= n; i++)
        cin >> a[i].f >> a[i].s;

    for (int i = 1; i <= n; i++)
    {
        sto.clear();
        for (int j = 1; j <= n ;j++)
        {
            if (i == j)
                continue;
            t = {a[j].f - a[i].f, a[j].s - a[i].s};
            st = __gcd(t.f, t.s);
            t.f /= st;
            t.s /= st;
            sto[t]++;
        }


        for (it = sto.begin(); it != sto.end(); it++)
        {
            t = (*it).f;
            k = (*it).s;
            if (k == 0)
                continue;
            k1 = 0;
            k2 = 0;

            t1 = {t.f, -t.s};
            if (t1 != t)
                k1 = sto[t1];

            t2 = {-t.s, t.f};
            if (t2 != t)
                k2 = sto[t2];

            ans += k * k1 + k * k2;
        }
    }

    cout << ans;
}