#include <fstream>

using namespace std;

ifstream cin("trapez.in");
ofstream cout("trapex.out");

struct punct {
	int x;
	int y;
};

struct verificam {
	int ok=0;
	int dif;
};

int main()
{
	int n,maxx=INT_MIN,maxy=INT_MIN;
	punct v[999];
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> v[i].x >> v[i].y;
		if (v[i].x > maxx)
			maxx = v[i].x;
		if (v[i].y > maxy)
			maxy = v[i].y;
	}
	verificam a[1001], b[1001];
	for (int i = 0; i < n-2; i++)
	for(int j=i+1;j<n;j++)
	{
		if (v[i].x == v[j].x and v[i].y != v[j].y)
		{
			a[i].ok++;
			a[i].dif = abs(v[i].y - v[j].y);
		}
		if (v[i].y == v[j].y and v[i].x != v[j].x)
		{
			b[i].ok++;
			b[i].dif = abs(v[i].x - v[j].x);
		}
	}
	int raspuns = 0;
	for (int i = 0; i < max(maxy,maxx); i++)
	for(int j=0;j<max(maxy,maxx);j++)
	{
		if(a[i].ok>0&&b[j].ok>0)
		{
			if (a[i].dif != b[j].dif)
				raspuns++;
		}

	}
	cout << raspuns/2;
}