#include <stdio.h>
#include <cstdlib>


struct punct
 {
  public:
	  long x,y;
 };

int main()
{

  FILE *in=fopen("trapez.in","r"),*out=fopen("trapez.out","w");

  int N;
  fscanf(in,"%d",&N);
  punct t[N];

  for(int i=0;i<N;i++)
    {
		fscanf(in,"%l",&t[i].x);
		fscanf(in,"%l",&t[i].y);
    }

int dx,dy,Dx,Dy,R=0;

for(int i1=0;i1<N;i1++)
 for(int i2=i1+1;i2<N;i2++)
   for(int i3=i2+1;i3<N;i3++)
     for(int i4=i3+1;i4<N;i4++)
       {
           dx= labs(t[i1].x-t[i2].x);
           dy= labs(t[i1].y-t[i2].y);
           Dx= labs(t[i3].x-t[i4].x);
           Dy= labs(t[i3].y-t[i4].y);


           if(dx/dy == Dx/Dy) R++;

           dx= labs(t[i3].x-t[i2].x);
           dy= labs(t[i3].y-t[i2].y);
           Dx= labs(t[i1].x-t[i4].x);
           Dy= labs(t[i1].y-t[i4].y);

           if(dx/dy == Dx/Dy) R++;

       }


fprintf(out,"%d",R);

}