#include <stdio.h>
#include <stdlib.h>
#include <math.h>
struct punct{
double x;
double y;
} a[1501];
int n;
void sw(double *a,double *b)
{
double t=*a; *a=*b; *b=t;
}
void qs(int left,int right)
{
int i,j; double p;
i=left; j=right; p=a[(i+j)/2].x;
while (i<j)
{
while (a[i].x<p) i++;
while (a[j].x>p) j--;
if (i<=j) {sw(&a[i].x,&a[j].x); sw(&a[i].y,&a[j].y); i++; j--;}
}
if (i<right) qs(i,right);
if (j>left) qs(left,j);
}
int egal(double a,double b)
{
if (abs(a-b)<=0.001) return 1; else return 0;
}
int cautare_bin(double x,int left,int right)
{
int i,j,p;
i=left; j=right; p=(i+j)/2;
//printf("%i %i %i %lf\n",i,j,p,x);
if (i==j)
{
if (egal(x,a[i].x)) return i; else return -1;
} else
if (x>=a[i].x && x<=a[p].x) cautare_bin(x,i,p); else
if (x>=a[p+1].x && x<=a[j].x) cautare_bin(x,p+1,j); else return -2;
}
int main()
{
int i,j,x2,k=0; double x1,y1;
freopen("triang.in","r",stdin);
freopen("triang.out","w",stdout);
scanf("%i",&n);
for (i=1; i<=n; i++) scanf("%lf%lf",&a[i].x,&a[i].y);
qs(1,n);
// for (i=1; i<=n; i++) printf("%lf %lf\n",a[i].x,a[i].y);
for (i=1; i<=n-2; i++)
{
for (j=i+1; j<=n-1; j++)
{
x1=a[i].x+(a[j].x-a[i].x)*0.5-(a[j].y-a[i].y)*sqrt(3)/2;
y1=a[i].x+(a[j].x-a[i].x)*sqrt(3)/2+(a[j].y-a[i].y)*0.5;
x2=cautare_bin(x1,j+1,n);
if (x2>0)
{
while (egal(x1,a[x2].x))
{
if (egal(a[x2].y,y1)) {k++; break;}
x2++;
}
}
//printf("%lf %lf %lf %lf %lf %lf %i %i\n",a[i].x,a[i].y,a[j].x,a[j].y,x1,y1,x2,k);
x1=a[i].x+(a[j].x-a[i].x)*0.5-(a[j].y-a[i].y)*(-0.866025403);
y1=a[i].x+(a[j].x-a[i].x)*(-0.866025403)+(a[j].y-a[i].y)*0.5;
x2=cautare_bin(x1,j+1,n);
if (x2>0)
{
while (egal(x1,a[x2].x))
{
if (egal(a[x2].y,y1)) {k++; break;}
x2++;
}
}
//printf("%lf %lf %lf %lf %lf %lf %i %i\n",a[i].x,a[i].y,a[j].x,a[j].y,x1,y1,x2,k);
}
}
printf("%i",k);
return 0;
}