#include <fstream>
#include <algorithm>
#include <cmath>
#include <set>

using namespace std;
const double EPS = 1e-5;

struct Punct
{
    double x, y;

    bool operator == (const Punct& A) const
    {
        return abs(x - A.x) <= EPS && abs(y - A.y) <= EPS;
    }

    bool operator < (const Punct& A) const
    {
        if(abs(x - A.x) <= EPS)
            return y + EPS  <= A.y;
        return x + EPS <= A.x;
    }

    bool operator > (const Punct& A) const
    {
        return *this < A;
    }
};

int N;
Punct P[1501];

set<Punct> S;

ofstream g("triang.out");
ifstream f("triang.in");

Punct rotire(const Punct &A, const Punct &B)
{
    static double c = 0.5, s = sqrt(3) / 2;
    double dx = B.x - A.x, dy = B.y - A.y;
    Punct C;
    C.x = dx * c - dy * s + A.x;
    C.y = dx * s + dy * c + A.y;
    return C;
}

int main()
{
    int i, j, nrTr = 0;
    f >> N;
    for(i = 1; i <= N; i++)
        f >> P[i].x >> P[i].y;
    //
    sort(P + 1, P + N + 1);
    //
    Punct M;
    for(i = 1; i <= N; i++)
    {
        for(j = 1; j < i; j++)
        {
            M = rotire(P[i], P[j]);
            if(S.find(M) != S.end())
                nrTr++;
        }
        S.insert(P[i]);
    }
    g << nrTr;
    return 0;
}