#include<iostream>
#include<fstream>
#include<vector>
#include<cmath>
#define P 123457
#define Q 1001
#define nmax 1009

using namespace std;

ifstream fin ("patrate3.in");
ofstream fout ("patrate3.out");

struct coord{
   long long int x, y;
};

int n, cnt;
vector <coord> L[P];
coord a[nmax];

void Citire()
{
    int i, j;
    long long int nr1, nr2, R;
    float x, y;
    coord q;
    fin >> n;

    for (i=1; i<=n; i++)
    {
        fin >> x >> y;
        nr1 = 1LL * x * 10000;  nr2 = 1LL * y * 10000;
        a[i].x = nr1; a[i].y = nr2;
        R = (nr1*Q + nr2) % P;
        q.x = nr1;  q.y = nr2;
        L[R].push_back(q);
    }
}

void Cauta(long long int x2, long long int y2, long long int x3, long long int y3)
{
   int found1, found2, j;
   long long int R;
   found1 = found2 = 0;

   R = (x2*Q + y2) % P;

   for (j=0; j<L[R].size() && !found1; j++)
      if (L[R][j].x == x2 && L[R][j].y == y2)
            found1 = 1;

    if (!found1) return;
    R = (x2*Q + y2) % P;

     for (j=0; j<L[R].size() && !found2; j++)
      if (L[R][j].x == x3 && L[R][j].y == y3)
            found2 = 1;

   if (found1 == 1 && found2 == 1) cnt++;
}

void Verifica(long long int x0, long long int y0, long long int x1, long long int y1)
{
     int i, j;
     long long int dx, dy, x2, y2, x3, y3;

     dx = x1 - x0;
     dy = y1 - y0;

     x2 = x1 + dy;
     y2 = y1 -  dx;
     x3 = x0 + dy;
     y3 = y0  - dx;

     Cauta(x2, y2, x3, y3);

     x2 = x1 -  dy;
     y2 = y1 + dx;
     x3 = x0 - dy;
     y3 = y0 + dx;

     Cauta(x2, y2, x3, y3);
}

void Rezolva()
{
     int i, j;
     long long int x0, y0, x1, y1;
     for (i=1; i<=n; i++)
     {
       for (j=i+1; j<=n; j++)
        {
            x0 = a[i].x;  y0 = a[i].y;
            x1 = a[j].x;  y1 = a[i].y;
            Verifica(x0, y0, x1, y1);
        }
     }

     fout << cnt << "\n";
}

int main ()
{
    Citire();
    Rezolva();
    fin.close();
    fout.close();
    return 0;
}