#include <fstream>
#include <unordered_map>
#include <cmath>
using namespace std;
ifstream fcin("triang.in");
ofstream fout("triang.out");
int n;
const double cos60 = 0.5;
const double sin60 = sqrt(3) / 2;
struct pct
{
    double x;
    double y;
    bool operator==(const pct &a) const
    {
        return x==a.x && y==a.y;
    }
};
pct v[2001];
struct HASH
{
    size_t operator()(const pct &a) const
    {
        return hash <long long>() ((hash<double>()(a.x)) ^ ((hash<double>()(a.y))<<32));
    }
};
unordered_map<pct,int, HASH> mp;
pct get_point( int i, int j )
{
  pct p1 = v[i], p2 = v[j], ret;
  ret.x = cos60 * (p1.x - p2.x) - sin60 * (p1.y - p2.y) + p2.x;
  ret.y = sin60 * (p1.x - p2.x) + cos60 * (p1.y - p2.y) + p2.y;
  return ret;
}
int main()
{
   fcin>>n;
   for(int i=1; i<=n; i++)
   {
       fcin>>v[i].x>>v[i].y;
       mp[v[i]]=1;
   }
   int rez=0;
   for(int i=1; i<=n; i++)
   {
       for(int j=1; j<i; j++)
       {
           pct g=get_point(i,j);
           fout<<g.x<<" "<<g.y<<"\n";
           if(mp.count(g))
            rez++;
       }
   }
   fout<<rez;
   return 0;
}