#include <fstream>
#include <algorithm>

#define abs(a) a<0?-a:a
#define lmax 1505

using namespace std;

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

int n,i,j,total,nr,nrr;

float y[lmax],x[lmax],dist[lmax*lmax];

int main()
{
    f>>n;

    for (i=1;i<=n;i++)
     f>>x[i]>>y[i];

    for (i=1;i<n;i++)
      for (j=i+1;j<=n;j++)

        dist[++nr]=(x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]);

    sort(dist+1,dist+nr+1);

    dist[nr+1]=dist[nr]-1;

    for (i=1;i<=nr+1;i++)
     if (abs(dist[i]-dist[i-1])>0.01)
      {
          total+=((nrr-2)*(nrr-1)*nrr)/6;

          nrr=1;
      }
     else
      nrr++;

     g<<total;

   f.close();
   g.close();
}