#include <fstream>
#include <cmath>
#include <unordered_set>
using namespace std;

ifstream cin("triang.in");
ofstream cout("triang.out");

const double rad3 = 1.73205081;

struct Point
{
  double x;
  double y;
};
bool operator== (Point a, Point b)
{
  return a.x == b.x && a.y == b.y;
}
Point p[15001];

struct MyHash{
  size_t operator()(const Point& val)const
  {
    return hash<double>()(val.x + val.y);
  }
};

unordered_set<Point, MyHash> myHash;
 
void adaugare (const Point& val)
{
  myHash.insert (val);
}
 
int cauta(const Point& val)
{
  if (myHash.find(val) != myHash.end())
    return 1;
  
  return 0;
}

void stergere (const Point& val)
{
  myHash.erase(val);
}

int main()
{
  int n; cin >> n;
  for (int i = 1; i <= n; ++i)
    {
      cin >> p[i].x >> p[i].y;
      
      p[i].x = round(p[i].x * 10000.0) / 10000.0;
      p[i].y = round(p[i].y * 10000.0) / 10000.0;

      adaugare(p[i]);
    }

  int cnt = 0;
  for (int i = 1; i <= n; ++i)
    for (int j = i + 1; j <= n; ++j)
      {
	double x1 = p[i].x + p[i].y * rad3 
	  + p[j].x - p[j].y * rad3;
	double y1 = -p[i].x * rad3 + p[i].y
	  + p[j].y + p[j].x * rad3;
	
	Point aux;
	aux.x = x1 / 2.0;
	aux.y = y1 / 2.0;

	aux.x = round(aux.x * 10000.0) / 10000.0;
	aux.y = round(aux.y * 10000.0) / 10000.0;

	if (cauta(aux) == 1)
	  ++cnt;

	x1 = p[i].x + p[j].x + 
	  (p[j].y - p[i].y) * rad3;
	y1 = p[i].x * rad3 + p[j].y +
	  p[i].y - p[j].x * rad3;
	
	aux.x = x1 / 2.0;
	aux.y = y1 / 2.0;

	aux.x = round(aux.x * 10000.0) / 10000.0;
	aux.y = round(aux.y * 10000.0) / 10000.0;
	
	if (cauta(aux) == 1)
	  ++cnt;
      }

  cout << cnt / 3;

  return 0;
}