#include <fstream>
#include <algorithm>
#include <cmath>
#include <cstdlib>

using namespace std;
ifstream fin("trapez.in");
ofstream fout("trapez.out");
const double  eps=1.e-14;
const double INF=1.e9;

class  POINT
{
  private : int x,y;
  public:
    POINT()

    {
        x=y=0;
    }
    POINT(int _x,int _y)
    {
        x=_x;
        y=_y;
    }
    POINT set(int _x,int _y)
    {
        x=_x;
        y=_y;
    }
    int getx()
    {
        return x;
    }
    int gety()
    {
        return y;
    }
    friend double panta(const POINT &a,const POINT &b)
    {
        if(a.x-b.x==0)
            return INF;
        double m=(double)(a.y-b.y),n=(double)(a.x-b.x);

        return m/n;
    }

};

POINT f[1005];
double p[500005];
int main()
{
    int n,u,v,nr=0,r=0,smax=0;
    fin>>n;
    for(int i=1;i<=n;i++)
    {
        fin>>u>>v;
        f[i].set(u,v);
    }
    for(int i=1;i<=n;i++)
    {
        for(int j=i+1;j<=n;j++)
        {
            nr++;
            p[nr]=panta(f[i],f[j]);
            //fout<<p[nr]<<endl;
        }
    }
    sort(p+1,p+nr+1);
    double y=p[1];
    r=1;
    for(int i=2;i<=nr;i++)
    {
        if(p[i]-y<eps)
        {
            r++;
        }
        else
        {
            smax+=r*(r-1)/2;
            r=1;
            y=p[i];
            //fout<<r<<endl;
        }
    }
    if(r!=1)
        smax+=r*(r-1)/2;
        //fout<<r<<endl;
    fout<<smax;
    return 0;
}