#include <stdio.h>
long x[1011],y[1011],n,i,j,l,q;
double a[1011000],c,b[10110000];
long long nr;
double modul(double x,double y)
{if(x-y>0)return x-y;else return y-x;}

void merge_sort(long st,long dr)
{long mij=st+((dr-st)>>1),i,j,k;
 if(st!=dr)
  {merge_sort(st,mij);
   merge_sort(mij+1,dr);
   for(i=st,j=mij+1,k=st;i<=mij||j<=dr;)
    if(j>dr||(i<=mij&&a[i]<a[j]))
     b[k++]=a[i++];
    else
     b[k++]=a[j++];
   for(k=st;k<=dr;k++)a[k]=b[k];
  }
}

int main()
{freopen("trapez.in","r",stdin);
 freopen("trapez.out","w",stdout);
 fscanf(stdin,"%ld",&n);
 for(i=1;i<=n;i++) fscanf(stdin,"%ld%ld",&x[i],&y[i]);
 for(i=2;i<=n;i++)
   for(j=1;j<i;j++)
    {if(x[i]!=x[j])a[++l]=double(y[i]-y[j])/double(x[i]-x[j]);else q++;
    }
 merge_sort(1,l);
 n=0;
 for(i=2;i<=l;i++)
  {if(modul(a[i-1],a[i])<0.0000000001)n++;else {nr+=n*(n+1)/2;n=0;}
  }
 nr+=n*(n+1)/2+q*(q-1)/2;
 fprintf(stdout,"%lld",nr);
 fclose(stdin);fclose(stdout);
 return 0;
}