#include<cstdio>
#define p first
#define x second.first
#define y second.second
#include<vector>
#define eps 1e-12
#define inf 2000000002
#include<algorithm>

using namespace std;

vector <pair<double,pair<int,int> > > s;
int n,nr,i,j,lg;
pair<int,pair<int,int> > a[1002];

double panta(int i,int j)
{
    double dy,dx;
    dy=a[i].y-a[j].y;
    dx=a[i].x-a[j].x;
    if(dx==0)
    {
        return inf;
    }
    return (dy/dx);
}

bool cmp(pair<double,pair<int,int> > i,pair<double,pair<int,int> > j)
{
    if(i.first+eps>j.first+eps)
    {
        return true;
    }
    return false;
}

int main()
{
    freopen("trapez.in","r",stdin);
    freopen("trapez.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<=n;i++)
    {
        scanf("%d%d",&a[i].x,&a[i].y);
    }
    for(i=1;i<n;i++)
    {
        for(j=i+1;j<=n;j++)
        {
            s.push_back(make_pair(panta(i,j),make_pair(i,j)));
        }
    }
    sort(s.begin(),s.end(),cmp);
    for(i=0;i<n*(n-1)/2;i++)
    {
        j=i;
        while(s[i].p-s[j].p>-eps&&s[i].p-s[j].p<eps)
        {
            j++;
        }
        j--;
        lg=j-i+1;
        nr+=lg*(lg-1)/2;
        i=j;
    }
    printf("%d\n",nr);
}