//#include<stdio.h>
//#include<conio.h>
#include<iostream.h>
#include<fstream.h>
#include<string.h>
#include<math.h>
 int n,j,i,m,f,k=0;
 double  a[3][2000];
  main()


{ clrscr();


 FILE *f1=fopen("triang.in","r");

 fscanf(f1,"%d",&n);

 for (i=1;i<=n;i++)
			   {
  fscanf(f1,"%lf",&a[1][i]);
  fscanf(f1,"%lf",&a[2][i]); }

 for(i=1;i<=n;i++)
 for(j=i+1;j<=n;j++)
    for(f=j+1;f<=n;f++)
   {
   double t=sqrt(pow(a[1][j]-a[1][i],2) +pow(a[2][j]-a[2][i],2));
   double b=sqrt(pow(a[1][f]-a[1][j],2) +pow(a[2][f]-a[2][j],2));
   double c=sqrt(pow(a[1][f]-a[1][i],2) +pow(a[2][f]-a[2][i],2));


   if (t+b>c && t+c>b && c+b>t )
   { if( fabs(b-c)<0.0001 && fabs(c-t)<0.0001 && fabs(t-b)<0.0001  ) k++; }

   }
     FILE *f2=fopen("triang.out","w");
   fprintf(f2,"%d",k);
	      fclose(f1);
	      fclose(f2);
      getche();
}