Kingdom of Cats

#include <iostream>
#include <cstdio>
#define task ""
using namespace std;
using ll = long long;
using ld = long double;

const int N = 50 + 2;
int n;
struct Point
{
    ll x, y;
    Point operator-(const Point &a)
    {
        Point ans;
        ans.x = x - a.x;
        ans.y = y - a.y;
        return ans;
    }
    ll operator*(const Point &a)
    {
        return x * a.y - y * a.x;
    }
} a[N];

void Read()
{
    for (int i = 1; i <= n; ++i)
        cin >> a[i].x >> a[i].y;
}

ll Online(int i, int j, int t)
{
    return (a[i] - a[j]) * (a[i] - a[t]) == 0ll;
}

void Solve()
{
    if (n < 4)
    {
        cout << "0\n";
        return;
    }
    ll ans = 0;
    for (int i = 1; i <= n; ++i)
        for (int j = i + 1; j <= n; ++j)
            for (int t = j + 1; t <= n; ++t)
                for (int h = t + 1; h <= n; ++h)
                    if (!Online(i, j, t) && !Online(i, t, h) && !Online(j, t, h) && !Online(i, j, h))
                        ++ans;
    cout << ans << "\n";
}

int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen(task ".INP", "r"))
    {
        freopen(task ".INP", "r", stdin);
        freopen(task ".OUT", "w", stdout);
    }
    while (cin >> n)
    {
        if (n == 0)
            break;
        Read();
        Solve();
    }
}