#include<fstream>
#include<algorithm>
using namespace std;
ifstream in("trapez.in");
ofstream out("trapez.out");

struct point{
	double x, y;
};

const int nmax = 1006;
const double eps = 0.000001;
int n, lvtan = 1, rasp, inf, p;
point v[nmax];
double vtan[nmax * nmax];

double modul(double x)
{
	if(x<0)
		return -x;
	else
		return x;
}

int main(){
	int player_unu=0;

	in>>n;
	for(int i = 1; i<=n; i++)
	{
		in>>v[i].x>>v[i].y;
	}

	for(int i = 1; i<=n; i++)
	{
		for(int j = i + 1; j<=n; j++)
		{
			if(v[i].y!=v[j].y)
			{
				vtan[lvtan] = (v[i].x - v[j].x) / (v[i].y - v[j].y);
				lvtan++;
			}
			else
			{
				inf++;
			}
		}
	}

	sort(vtan + 1, vtan + lvtan);

	vtan[0] = -1000000000;
	for(int i = 1; i<lvtan; i++)
	{
		if(modul(vtan[i] - vtan[i - 1])<eps)
		{
			p++;
		}
		else
		{
			rasp += p * (p - 1) / 2;
			p = 1;
		}
	}

	rasp += p * (p - 1) / 2;
	rasp += inf * (inf - 1) / 2;

	out<<rasp<<'\n';

	return player_unu;
}