#include <stdio.h>
#include <math.h>
#include <algorithm>

using namespace std;

FILE*f=fopen("triang.in","r");
FILE*g=fopen("triang.out","w");

int n,nr;

struct pct
{
    double x,y;
}v[1510];

int cmp(pct a,pct b)
{
    if (a.x<b.x||(fabs(a.x-b.x)<0.001&&a.y<b.y)) return 1;
    else return 0;
}

double p(double x)
{
    return x*x;
}

void cauta(double x, double y,int p)
{
    int u=n,m;
    while (p<u)
    {
        m=(p+u)/2;
        if ((fabs(v[m].x-x)<0.001)&&(fabs(v[m].y-y)<0.001)) {nr++;return;}
        else
        if (v[m].x>x||(fabs(v[m].x-x)<0.001&&v[m].y>y)) u=m;
        else p=m+1;
    }
    m=(p+u)/2;
    if ((fabs(v[m].x-x)<0.001)&&(fabs(v[m].y-y)<0.001)) {nr++;return;}
}

int main()
{
    int i,j;
    double x,y,dx,dy,sin,cos;
    sin=sqrt(3)/2.;
    cos=0.5;
    fscanf(f,"%d",&n);
    for (i=1;i<=n;i++)
    {
        fscanf(f,"%lf%lf",&v[i].x,&v[i].y);
    }
    sort(v+1,v+n+1,cmp);
    for (i=1;i<n;i++)
        for (j=i+1;j<n;j++)
        {
            dx=v[j].x-v[i].x;
            dy=v[j].y-v[i].y;
            x=v[i].x+dx*cos-dy*sin;
            y=v[i].y+dy*cos+dx*sin;
            cauta(x,y,j+1);
            x=v[i].x+dx*cos+dy*sin;
            y=v[i].y+dy*cos-dx*sin;
            cauta(x,y,j+1);
        }
    fprintf(g,"%d",nr);
    fclose(f);
    fclose(g);
    return 0;
}