#include <stdio.h>
long x[1011],y[1011],b[1011],n,i,j,l,q;
double a[10110000],c;
long long nr;
double modul(double x,double y)
{if(x-y>0)return x-y;else return y-x;}
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++;
    }
 for(i=1;i<l;i++)
  for(j=i+1;j<=l;j++)
   {if(a[i]>a[j]){c=a[i];a[i]=a[j];a[j]=c;}
   }
 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;
}