#include <cstdio>
#include <vector>
#include <cmath>
#include <algorithm>
#define INF 1.e9
#define eps 1.e-14;
using namespace std;
class POINT
{
private:
    double x,y;
public:
    POINT(){x=y=0;}
    void set(double x0,double y0){x=x0,y=y0;}
    bool vertical(const POINT &other){return x==other.x;}
    double panta(const POINT &other){if(vertical(other))return INF;return (other.y-y)/(other.x-x); }
};
vector <double> pan;
POINT a[1010];
int main()
{
    int n,i,j,sum=0,nr=0;
    double last,x,y;
    freopen("trapez.in","r",stdin);
    freopen("trapez.out","w",stdout);
    scanf("%d",&n);
    for(i=1; i<=n; i++)
    {
        scanf("%lf%lf",&x,&y);
        a[i].set(x,y);
    }
    for(i=1; i<n; i++)
        for(j=i+1; j<=n; j++)
            pan.push_back(a[i].panta(a[j]));
    sort(pan.begin(),pan.end());
    last=pan[0];
    nr=1;
    for(i=1; i<=pan.size()-1; i++)
        if(last==pan[i])
            nr++;
        else
        {
            if(nr>1)
                sum+=(nr*(nr-1)/2);
            nr=1;
            last=pan[i];
        }
        printf("%d\n",sum);
    return 0;
}