#include <iostream>
#include <fstream>
#include <vector>
#include <set>
#include <cmath>
using namespace std;

ifstream in("patrate3.in");
ofstream out("patrate3.out");

struct point
{
    int x, y;
};

inline bool operator<(const point& A, const point& B)
{
    return A.x < B.x || (A.x == B.x && A.y < B.y);
}


class FindSquares
{
    set < point > point_tree;
    vector < point > points;
    int squares = 0;

    void check_square(point A, point C)
    {
        point New1, New2;

        New1.x = (A.x + C.x + A.y - C.y) / 2;
        New1.y = (A.y + C.y + C.x - A.x) / 2;

        New2.x = (A.x + C.x + C.y - A.y) / 2;
        New2.y = (A.y + C.y + A.x - C.x) / 2;

        if(point_tree.find(New1) != point_tree.end() && point_tree.find(New2) != point_tree.end())
            ++squares;
    }

public:

    void add_point(float X, float Y)
    {
        point A;
        A.x = ceil(X * 10000);
        A.y = ceil(Y * 10000);
        point_tree.insert(A);
        points.push_back(A);
    }

    int solve()
    {
        for(int i = 0; i < points.size(); ++i)
            for(int j = 0; j < points.size(); ++j)
                if(i != j)
                    check_square(points[i], points[j]);

        return squares / 4;
    }

};

int main()
{
    FindSquares F;
    int n;
    float X, Y;

    in >> n;
    for(int i = 0; i < n; ++i)
    {
        in >> X >> Y;
        F.add_point(X, Y);
    }

    out << F.solve();
    return 0;
}