#include<stdio.h>

int n;
long i,j,x[1001],y[1001],k,a[50000],b[50000],nr,para;

int main()
{
 freopen("trapez.in","r",stdin);
 freopen("trapez.out","w",stdout);

 scanf("%d", &n);
 for(i=1;i<=n;i++)
     scanf("%ld %ld", &x[i],&y[i]);
 
 k=1;
 for(i=1;i<n;i++)
    for(j=i+1;j<=n;j++)
       {
        a[k]=y[i]-y[j];
        b[k]=x[i]-x[j];
        if(b[k]==0) para++;
        k++;
        }
 
 for(i=1;i<k;i++)
     for(j=i+1;j<=k;j++)
         {
         if(b[i]!=0 && b[j]!=0) //nu e paralela cu Oy
          if(a[i]*b[j]==a[j]*b[i]) 
                                   nr++;
          }
 
 nr+=((para-1)*para)/2;
 
 printf("%ld", nr);
 
 return 0;
}