// TrapezAgain.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>
#include <fstream>
#include <algorithm>

using namespace std;
typedef pair<int, int> directie;
ifstream f("trapez.in");
ofstream g("trapez.out");

directie Create(directie a,const directie& b)
{
    a.first-=b.first;
    a.second-=b.second;
	if (a.first == 0)
		return { 0,1 };
	if (a.second == 0)
		return { 1,0 };
	int g = __gcd(abs(a.first), abs(a.second));
	if(a.first < 0)
    {
        a.first = -a.first;
        a.second = -a.second;
    }
	return { a.first/g,a.second/g };
}
pair<int,int> puncte[1001];
directie dir[1000*1000+1];
int k;
int n;
int main()
{
    f>>n;
    for(int i=1;i<=n;i++)
        f>>puncte[i].first>>puncte[i].second;
    for(int i=1;i<n;i++)
        for(int j=i+1;j<=n;j++)
            dir[k++] = Create(puncte[i],puncte[j]);
    sort(dir,dir+k);

    int sol = 0;
    int last = 0;
    for(int i=1;i<k;i++)
        if(dir[last] != dir[i])
        {
            int nr = i - last;
            sol += nr*(nr-1)/2;
            last = i;
        }
    int nr = k - last;
    sol += nr*(nr-1)/2;
    g<<sol;
    f.close();
    g.close();
}