#include <iostream>
#include <algorithm>
#include <math.h>
#define lol long long

using namespace std;

FILE * fin = fopen("triang.in", "r");
FILE * fout = fopen("triang.out", "w");

int n;

double eps = 1e-3;

struct point
{
    double x, y;
};

bool comp(point p1, point p2)
{
    if (p1.x - eps > p2.x || p1.x + eps < p2.x)
        return p1.x < p2.x;
    if (p1.y - eps > p2.y || p1.y + eps < p2.y)
        return p1.y < p2.y;
    return false;
}

point points[1505];

int main()
{
    fscanf(fin, "%d", &n);
    for (int i = 0; i < n; i++)
        fscanf(fin, "%lf %lf", &points[i].x, &points[i].y);
    sort(points, points + n, comp);
    lol countt = 0;
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            if (i == j)
                continue;
            // rotate it both ways, verify if it exists
            double newX = points[i].x - points[j].x;
            double newY = points[i].y - points[j].y;
            double sin60 = sqrt(3) / 2;
            point p1 = {newX / 2 - sin60 * newY + points[j].x,
                        newX * sin60 + newY / 2 + points[j].y};
            countt += binary_search(points, points + n, p1, comp);
            point p2 = {newX / 2 + sin60 * newY + points[j].x,
                        - newX * sin60 + newY / 2 + points[j].y};
            countt += binary_search(points, points + n, p2, comp);
        }
    }
    fprintf(fout, "%lld\n", countt / 6);
}