#include <fstream>
#include <iostream>
#include <unordered_map>

using namespace std;

ifstream f("trapez.in");
ofstream g("trapez.out");

const int nmax = 1005;
int n, i, j, x, y;
double pnt;
struct punct {
    int x, y;
}v[1005];
long long sol;
unordered_map <long double, int> cnt2;
unordered_map <double, int> cnt;
long double p;

int main() {
    f >> n;
    for (i = 1; i <= n; i++) {
        f >> x >> y;
        v[i] = {x,y};
    }
    for (i = 1; i <= n; i++) {
        for (j = i+1; j <= n; j++) {
            if (v[j].x == v[i].x) {
                if (v[j].y > v[i].y)
                    pnt = -2e9-5;
                else pnt = -2e9-6;
            }
            else pnt = (double)(v[j].y-v[i].y)/(v[j].x-v[i].x);
            cnt[pnt]++;
            p = i*4.01e9+pnt+2e9+10;
            cnt2[p]++;
        }
    }
    for (i = 1; i <= n; i++) {
        for (j = i+1; j <= n; j++) {
            if (v[j].x == v[i].x) {
                if (v[j].y > v[i].y)
                    pnt = -2e9+5;
                else pnt = -2e9+6;
            }
            else pnt = (double)(v[j].y-v[i].y)/(v[j].x-v[i].x);
            p = i*4.01e9+pnt+2e9+10;
            y = cnt2[p];
            x = cnt[pnt]-y;
            if (y) sol += (x*y);
            cnt2[p] = 0;
        }
    }

    g << sol/2;
    return 0;
}