#include <bits/stdc++.h>

#define forn(i, n) for(int i = 0; i < (int)(n); ++i)

using namespace std;

struct pt
{
    int x, y;
};

pt operator-(const pt &a, const pt &b)
{
    pt res;
    res.x = b.x - a.x;
    res.y = b.y - a.y;
    return res;
}

int64_t vec_mult(const pt &a, const pt &b)
{
    return (int64_t)(a.x) * b.y - (int64_t)(a.y) * b.x;
}

int64_t scal_mult(const pt &a, const pt &b)
{
    return (int64_t)(a.x) * b.x + (int64_t)(a.y) * b.y;
}

int main()
{
    int n;
    cin >> n;
    vector<pt> p(n);
    int ans = 0;
    forn (i, n) cin >> p[i].x >> p[i].y;
    sort(p.begin(), p.end());
    for (int i = 0; i < n - 2; ++i) // a
    {
        for (int j = i + 1; j < n - 1; ++j) // b
        {
            for (int m = j + 1; m < n; ++m) // c
            {
                if (scal_mult(p[m] - p[j], p[i] - p[m]) == 0) ++ans;
            }
        }
    }
    cout << ans << "\n";
    return 0;
}