#include<fstream>
#include<algorithm>

using namespace std;

ifstream f ("trapez.in");
ofstream g ("trapez.out");

int n,nrs,nrt;

struct punct{
			int x,y,fol;
			};
punct p[1001],m[499501];

void read_calcpanta()
{
	int i,j;
	f >> n;
	for(i = 1 ; i <= n ; i++)
		f >> p[i].x >> p[i].y;
	for(i = 1 ; i < n ; i++ )
		for(j = i+1 ; j <= n ; j++)
			{
				m[++nrs].x = p[i].x - p[j].x;
				m[nrs].y = p[i].y - p[j].y;
			}
}

int main ()
{
	read_calcpanta();
	int i,j,nr;
	for(i = 1 ; i < nrs; i++)
		{
			nr = 1;
			for( j = i+1 ; j <= nrs ; j++)
				if(m[i].x * m[j].y == m[j].x * m[i].y)
					nr++;
			nrt = nrt + nr*(nr-1)/2;
		}
	g << nrt << '\n';
	f.close();
	g.close();
	return 0;
}