#include <iostream>
#include <fstream>
#include <set>
#include <string>
#include <cmath>

std::ifstream f("patrate3.in");
std::ofstream g("patrate3.out");
 

std::set<std::pair<int, int> > map;
struct {
	int x, y;
}patrate[1000];

int n;

int main()
{
	f >> n;
	
	float x, y;
	for (int i = 0; i < n; ++i)
	{
		f >> x >> y;

		patrate[i].x = round(x * 10000.0f);
		patrate[i].y = round(y * 10000.0f);

		map.insert({ patrate[i].x, patrate[i].y });
	}

	long long total = 0;

	int x1, y1, x2, y2, x3, y3, x4, y4;
	for (int i = 0; i < n; ++i)
		for (int j = 0; j < n; ++j)
		{
			if (patrate[i].x == patrate[j].x && patrate[j].y == patrate[i].y)
				continue;

			x1 = patrate[i].x;
			y1 = patrate[i].y;
			x2 = patrate[j].x;
			y2 = patrate[j].y;
			
			//  pct 1  ________ pct 4
			//         |	   |
			//         |       |
			//         |_______|
			//  pct 2           pct 3

			// rotesc pct 1 in jurul pct 2 cu -90 grade (in sens trigonometric), (adica din x1, y1 scad x2, y2, rotesc (x,y) -> (y, -x) , si dupa adun x2, y2 inapoi)
			x3 = y1 - y2 + x2;
			y3 = x2 - x1 + y2;

			// fac acelasi lucru pt pct 2 doar ca in rotesc cu 90 grade (x, y) -> (-y, x)
			x4 = y1 - y2 + x1;
			y4 = x2 - x1 + y1;

			if (map.find({ x3,y3 }) != map.end() && map.find({ x4,y4 }) != map.end())
				total++;
		}

	g << total / 4; // fiecare patrat e numarat de 4 ori
}