#include<stdio.h>
#define M 500000

long sol[M][2],x[1001],y[1001],j,i,nr,q;
int n;

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]);
                      for(j=1;j<i;j++)
                      {
                                      q++;
                                      sol[q][0]=y[i]-y[j];
                                      sol[q][1]=x[i]-x[j];
                      }
    }
    for(i=1;i<q;i++)
       for(j=i+1;j<=q;j++)
           if (sol[i][0]*sol[j][1]==sol[j][0]*sol[i][1])
                  nr++;
    printf("%ld\n",nr);
    return 0;
}