//https://github.com/bicsi/kactl/blob/master/content/geometry/Point.hs

#include<bits/stdc++.h>
using namespace std;
#pragma once

using Point = complex<double>;

const double kPi = 4.0 * atan(1.0);
const double eps = 1e-7; // Good eps for long double is ~1e-11

#define X() real()
#define Y() imag()

double dot(Point a, Point b) { return (conj(a) * b).X(); }
double cross(Point a, Point b) { return (conj(a) * b).Y(); }
double dist(Point a, Point b) { return abs(b - a); }
Point perp(Point a) { return Point{-a.Y(), a.X()}; } // +90deg

Point rotateCCW(Point a, double theta) {
  return a * polar(1.0, theta); }
double det(Point a, Point b, Point c) {
  return cross(b - a, c - a); }

// abs() is norm (length) of vector
// norm() is square of abs()
// arg() is angle of vector
// det() is twice the signed area of the triangle abc
// and is > 0 iff c is to the left as viewed from a towards b.
// polar(r, theta) gets a vector from abs() and arg()

void ExampleUsage() {
  Point a{1.0, 1.0}, b{2.0, 3.0};
  cerr << a << " " << b << endl;
  cerr << "Length of ab is: " << dist(a, b) << endl;
  cerr << "Angle of a is: " << arg(a) << endl;
  cerr << "axb is: " << cross(a, b) << endl;
}
bool cmp(Point a,Point b)
{
    if(a.X()==b.X()) return a.Y()<b.Y();
    return a.X()<b.X();
}

inline bool isIn(const Point& p,const vector<Point>& v)
{
    int n=(int)v.size();

    int st=0;
    int dr=n-1;
    int sol=-1;
    while(st<=dr)
    {
        int mid=(st+dr)>>1;
        if(fabs(v[mid]-p)<eps)
        {
            sol=mid;
            break;
        }
            else
        if(!cmp(p,v[mid]))
            st=mid+1;
        else
            dr=mid-1;
    }

    if(sol!=-1) return 1;
    return 0;
}
int main()
{
    ifstream fin("patrate3.in");
    ofstream fout("patrate3.out");

    vector<Point> v;
    int n;
    int sol=0;

    fin>>n;
    for(int i=1;i<=n;i++)
    {
        double x,y;
        fin>>x>>y;

        v.push_back(Point(x,y));
    }

    sort(v.begin(),v.end(),cmp);



    for(int i=0;i<n;i++)
    {
        for(int j=0;j<n;j++)
        {
            if(i==j) continue;

            Point a=v[i],b=v[j];
            Point c=rotateCCW(b-a,3.0*kPi/2.0)+a;
            Point d=rotateCCW(a-b,kPi/2.0)+b;
            if(isIn(c,v) && isIn(d,v))
                sol++;
        }
    }

    fout<<sol/4<<'\n';
    return 0;
}