int gcd (int a, int b) {
	while (b) {
		a %= b;
		swap (a, b);
	}
	return a;
}

signed main() {
#ifdef DEBUG
	fr("input.txt");
	// fw("output.txt");
#else
	fr("input.txt");
	fw("output.txt");
#endif
	int n;
	cin >> n;
	vector<pair<int, int> > pt(n);
	int ans = 0;
	for(int i = 0; i < n; i++) cin >> pt[i].f >> pt[i].s;
	for(int i = 0; i < n; i++){
		int d = 0;
		map<pair<int, int>, int> kek;
		for(int j = 0; j < n; j++){
			if(i == j) continue;
			int dx = pt[i].f - pt[j].f;
			int dy = pt[i].s - pt[j].s;
			int g = gcd(dx, dy);
			if(g != 0){
				dx /= g;
				dy /= g;
			}
			kek[{dx, dy}]++;
		}
		for(auto &a: kek){
			// cout << a.first.first << ' ' << a.first.second << ':' << a.second << endl;
			d += a.second * kek[{a.first.second, -a.first.first}];
			d += a.second * kek[{-a.first.second, a.first.first}];
		}
		ans += d / 2;
		// cout << d << endl;
	}
	cout << ans;

}