#include <fstream>
using namespace std;
ifstream f("trapez.in");
ofstream g("trapez.out");
struct punct{long x,y;}a[1002];
int n,i,j,k=1,l;
double b[500000];
long nr;
double panta(punct p1,punct p2)
{
    return (float)(p1.y-p2.y)/(p1.x-p2.x);
}
/*void interc(long st,long m,long dr)
{
    double c[dr-st+2];
    long i=st,j=m+1,k=0;
    while(i<=m && j<=dr)
        if(b[i]<b[j]) c[++k]=b[i++];
        else c[++k]=b[j++];
    for(;i<=m;i++) c[++k]=b[i];
    for(;j<=dr;j++) c[++k]=b[j];
    for(i=st;i<=dr;i++) b[i]=c[i-st+1];
}*
void mergesort(long st,long dr)
{
    if(st>=dr) return;
    long m=(st+dr)>>1;
    mergesort(st,m);
    mergesort(m+1,dr);
    interc(st,m,dr);
}*/
int main()
{
    f>>n;
    for(i=1;i<=n;i++) f>>a[i].x>>a[i].y;
    for(i=1;i<n;i++)
        for(j=i+1;j<=n;j++)
        b[++l]=panta(a[i],a[j]);
    double auxi;
    for(i=1;i<l;i++)
        for(j=i+1;j<=l;j++)
    if(b[i]>b[j]) {auxi=b[i];b[i]=b[j];b[j]=auxi;}
    for(i=2;i<=l;i++)
    {
        if(b[i]==b[i-1]) k++;
        else nr+=k*(k-1)/2,k=1;
    }
    g<<nr;
    f.close();g.close();
    return 0;
}