#include <iostream>
#include <fstream>
using namespace std;
typedef struct {int x,y;} PUNCT;
typedef struct {int aa,bb;} DREAPTA;
ifstream fi("trapez.in");
ofstream fo("trapez.out");
int n,i,j,k,rez;
PUNCT P[1005];
DREAPTA D[1000005];
int main()
{
	fi>>n;
	for (i=1;i<=n;i++)
		fi>>P[i].x>>P[i].y;
	k=0;
	for (i=1;i<=n;i++)
		for (j=i+1;j<=n;j++)
		{
			k++;
			D[k].aa=P[i].y-P[j].y;
			D[k].bb=P[i].x-P[j].x;
		}
	/*
	for (i=1;i<=k;i++)
	{
		t1=D[i].a;
		t2=D[i].b;
		cout<<P[t1].x<<" "<<P[t1].y<<" "<<P[t2].x<<" "<<P[t2].y<<" "<<D[i].aa<<" "<<D[i].bb<<" "<<D[i].p<<endl;
	}
	*/
	for (i=1;i<=k;i++)
		for (j=i+1;j<=k;j++)
		{
			if (D[i].aa*D[j].bb==D[i].bb*D[j].aa)
				rez++;
		}
	
	fo<<rez<<endl;
	
	return 0;
}