#include <stdio.h>
#include <stdlib.h>
#include <math.h>
double polar(double,double);
void qs(int,int);
void sw(double *a,double *b);
void init();
int n;
double x[1501],y[1501],h[1501];
double polar(double x,double y)
{
if (x>0)
if (y>0) return atan(y/x); else return atan(y/x)+3.14*3;
if (x<0) return 3.14+atan(y/x);else
if (x==0)
if (y>0) return 3.14/2; else
if (y<0) return 3.14*3/2; else
return 0;
}
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=h[(i+j)/2];
while (i<j)
{
while (h[i]<p) i++;
while (h[j]>p) j--;
if (i<=j) {sw(&h[i],&h[j]); i++; j--;}
}
if (i<right) qs(i,right);
if (j>left) qs(left,j);
}
void init()
{
int i; double px,py;
for (i=1; i<=n; i++) scanf("%f%f",&x[i],&y[i]);
px=x[1]; py=y[1];
for (i=2; i<=n; i++)
if (py>y[i]) { py=y[i]; px=y[i];}
for (i=1; i<=n; i++) h[i]=polar(x[i]-px,y[i]-py);
}
double dist(double x1,double y1,double x2,double y2)
{
return sqrt(pow(abs(x1-x2),2)+pow(abs(y1-y2),2));
}
int main()
{
int k,i,j,c; double a,b,d;
freopen("triang.in","r",stdin);
freopen("triang.out","w",stdout);
scanf("%i",&n);
init();
qs(1,n);
k=0;
for (i=1; i<=n-2; i++)
for (j=i+1; j<=n-1; j++)
for (c=j+1; c<=n; c++)
{
a=dist(x[i],y[i],x[j],y[j]); b=dist(x[i],y[i],x[c],y[c]); d=dist(x[c],y[c],x[j],y[j]);
if (a==b && a==d && d==b) k++;
}
printf("%i",k);
return 0;
}