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

using namespace std;
const double EPS = 1e-5,
             R3 = sqrt(3.0);

struct Punct
{
    double x, y;
};

int N;
Punct P[1501];

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

int egal(double a, double b)
{
    double d = a - b;
    if(d < -EPS)return -1;
    if(d > +EPS)return +1;
    return 0;
}

int egal(const Punct &A, const Punct &B)
{
    int ex = egal(A.x, B.x),
        ey = egal(A.y, B.y);
    if(ex == 0) return ey;
    return ex;
}

bool comp(const Punct &A, const Punct &B)
{
    return egal(A, B) < 0;
}

bool cautbin(const Punct &A)
{
    int p = 1, u = N;
    while(p <= u)
    {
        int m = (p + u) / 2;
        int e = egal(P[m], A);
        if(e == 0)
            return 1;
        if(e == 1)
            u = m - 1;
        else
            p = m + 1;
    }
    return 0;
}


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, comp);
    //
    double ddx, ddy;
    Punct M, C, D;
    for(i = 1; i < N; i++)
        for(j = i + 1; j <= N; j++)
        {
            M.x = (P[i].x + P[j].x) / 2;
            M.y = (P[i].y + P[j].y) / 2;
            ddx = R3 * (P[j].y - M.y);
            ddy = R3 * (P[j].x - M.x);
            C.x = M.x - ddx;
            C.y = M.y + ddy;
            D.x = M.x + ddx;
            D.y = M.y - ddy;
            nrTr += cautbin(C);
            nrTr += cautbin(D);
        }
    g << nrTr / 3;
    return 0;
}