#include<iostream>
#include<vector>
#include<algorithm>
#include<fstream>
#define infinit 9000000000
using namespace std;
typedef long long ll;
typedef pair<ll, ll> punct;
ifstream f("trapez.in");
ofstream g("trapez.out");
int N;
vector<punct> puncte;
vector<double> pante;
int rezultat;
void citire()
{
	f >> N;
	for (int i = 1; i <= N; i++)
	{
		int x, y;
		f >> x >> y;
		puncte.push_back(make_pair(x, y));
	}
	for (int i = 0; i <= N-1; i++)
		cout << puncte[i].first << " " << puncte[i].second << endl;
}
double make_panta(punct a, punct b)
{
	if (a.first == b.first)
		return infinit ;
	else
	    return (a.second - b.second)/ (double)(a.first - b.first);
}

void rezolvare()
{
	
	int contor = 1;
	for (size_t i = 0; i < N - 1; i++)
		for (size_t j = i + 1; j < N; j++)
			pante.push_back(make_panta(puncte[i], puncte[j]));
			//cout << puncte[i].first << " " << puncte[i].second << " + " << puncte[j].first << " " << puncte[j].second << endl;
	sort(pante.begin(), pante.end(), [](double a, double b) {return a < b; });
	for (size_t i = 1; i < pante.size(); i++)
		if (pante[i] == pante[i - 1])
			contor++;
		else
		{
			rezultat += contor * (contor - 1) / 2;
			contor = 1;
		}
	     
	g << rezultat;

}
int main()
{
	citire();
	rezolvare();
	return 0;
}