#include <cstdio>
#include <vector>
#include <algorithm>
#define eps 1e-12
#define mp make_pair
#define qup 2000000000

using namespace std;
long long result=0LL;
int x,y,i,j,n,nr,k;
vector<double> a;
vector<pair<int,int> > b;

double panta(int i,int j)
{
    int X,Y;

    X=b[i].first-b[j].first;
    Y=b[i].second-b[j].second;

    if(X==0) return qup+1;
    return (double)Y/X*1.0;
}

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

    scanf("%d",&n);

    for(i=1; i<=n; ++i)
    {
        scanf("%d%d",&x,&y);
        b.push_back(mp(x,y));
    }

    k=0;
    for(i=0; i<n-1; ++i)
        for(j=i+1; j<n; ++j)
        {
            a.push_back(panta(i,j));
            ++k;
        }

    sort(a.begin(),a.end());

    for(i=0; i<k-1; ++i)
    {
        nr=1;
        while(a[i]-a[i+1]<eps && a[i+1]-a[i]<eps)
        {
            ++nr;
            if(i+1==k-1) break;
            ++i;
        }
        result+=1LL*nr*(nr-1)/2;
    }


    printf("%lld\n",result);

    return 0;
}