/// Preset de infoarena
#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

ifstream fin("trapez.in");
ofstream fout("trapez.out");

struct point {
    int x, y;
}pct[1005];
vector <pair <int, int>> v;
long long ans;

int euclid(int a, int b)
{
    if(b == 0)
        return a;
    return euclid(b, a % b);
}

int main()
{
    int n;
    fin >> n;
    for(int i = 1; i <= n; i++)
        fin >> pct[i].x >> pct[i].y;
    int k = 0;
    for(int i = 1; i <= n; i++)
    {
        for(int j = i + 1; j <= n; j++)
        {
            if(pct[i].y == pct[j].y)
                k++;
            else
            {
                int deltax = pct[i].x - pct[j].x, deltay = pct[i].y - pct[j].y;
                int cmmdc = euclid(deltax, deltay);
                deltax /= cmmdc;
                deltay /= cmmdc;
                v.push_back({deltax, deltay});
            }
        }
    }
    sort(v.begin(), v.end());
    ans = 1LL * k * (k - 1) / 2;
    k = 1;
    for(int i = 1; i < v.size(); i++)
    {
        if(v[i] == v[i - 1])
            k++;
        else
        {
            ans += 1LL * k * (k - 1) / 2;
            k = 1;
        }
    }
    ans += 1LL * k * (k - 1) / 2;
    fout << ans;
    return 0;
}