#include <stdio.h>
#include <math.h>
using namespace std;
int n,RES=0;
struct dpoint
{
 double x,y;
}p[1500];


double dist(double x1,double y1,double x2,double y2)
{
    return sqrt( (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2) );
}

void _read()
{
    freopen("triang.in","r",stdin);
    freopen("triang.out","w",stdout);

    scanf("%d",&n);
    for(int i=0;i<n;i++)
      scanf("%lf %lf",&p[i].x,&p[i].y);
}

int main()
{
_read();
int i,j,k;

for( i=0;i<n;i++)
  for( j=i+1;j<n;j++)
    for( k=j+1;k<n;k++)
    {
        if(dist( p[i].x,p[i].y,p[j].x,p[i].y) - dist( p[i].x,p[i].y,p[k].x,p[k].y) <= 0.001   )
          if( dist(p[i].x,p[i].y,p[j].x,p[j].y) - dist(p[j].x,p[j].y,p[k].x,p[k].y) <= 0.001  )
              RES++;
   }


printf("%d",RES);

return 0;
}