#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
const double eps=1.e-14;
const double INF=2.e9;
struct POINT
{
	double x,y;
};
bool vertical(POINT p1,POINT p2)
{
	return fabs(p1.x-p2.x)<eps;
}
double panta(POINT p1,POINT p2)
{
	if(vertical(p1,p2))
		return INF;
  return (p2.y-p1.y)/(p2.x-p1.x);
}
POINT points[1005];
double ang[500005];
int main()
{
    freopen("trapez.in","r",stdin);
    freopen("trapez.out","w",stdout);
    int n,i,x,y,j,nr,flag,l;
    long long rez;
    scanf("%d",&n);
    for(i=1;i<=n;i++)
		{
      scanf("%d%d",&x,&y);
      points[i].x=x;
      points[i].y=y;
		}
    nr=0;
    for(i=1;i<=n;i++)
        for(j=i+1;j<=n;j++)
          ang[++nr]=panta(points[i],points[j]);
    sort(ang+1,ang+nr+1);
    rez=0;
    flag=0;
    l=0;
    for(i=nr;ang[i]==INF;--i)
        nr--;
    for(i=1;i<=nr;i++)
    {
        if(fabs(ang[i]-ang[i-1])<eps && flag==0){
            flag=1;
            l=0;
        }
        if(fabs(ang[i]-ang[i-1])<eps && flag==1)
            l++;
        if(fabs(ang[i]-ang[i-1])>eps && flag==1)
        {
            rez=rez+l*(l+1)/2;
            flag=0;
        }
    }
    printf("%d",rez);
    return 0;
}