#include <fstream>
#include <bits/stdc++.h>

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

struct punct
{
double x,y;}p[1501];



int comp(punct a, punct b)
{
  return(abs(a.x-b.x)<0.001&&a.x<b.y||a.x<b.x);
}
int n,k;
void cbin(double x,double y)
{
int st,dr,mij;
st=1;dr=n;
while(st<=dr)
{
mij=(st+dr)/2;
if(abs(x-p[mij].x)<0.001 && abs(y-p[mij].y)<0.001) {k++;return;}
if(x-p[mij].x<0.001 || (abs(x-p[mij].x)<0.001 && y-p[mij].y<0.001)) dr=mij-1;
    else st=mij+1;
}

}
double xx,yy;
int main()
{
int i,j;
f>>n;
for(i=1;i<=n;i++)
f>>p[i].x>>p[i].y;
sort(p+1,p+n+1,comp);
for (i=1;i<=n;i++)
{
for(j=i+1;j<=n;j++)
{
xx=p[i].x+(p[j].x-p[i].x)/2-sqrt(3)*(p[j].y-p[i].y)/2;
yy=p[i].y+sqrt(3)*(p[j].x-p[i].x)/2+(p[j].y-p[i].y)/2;
cbin(xx,yy);
xx=p[i].x+(p[j].x-p[i].x)/2+sqrt(3)*(p[j].y-p[i].y)/2;
yy=p[i].y-sqrt(3)*(p[j].x-p[i].x)/2+(p[j].y-p[i].y)/2;
cbin(xx,yy);
}
}
g<<k/3;
    return 0;
}