#include <iostream>
#include <fstream>
using namespace std;
int n;
float coordonate[2000];
float panta[100];
int j=0,i=0;
int trapez_cout=0;
void read()
{
    ifstream trapez;
    trapez.open("trapez.in");
    trapez>>n;
    while(!trapez.eof())
    {
        trapez>>coordonate[i];
        i++;
    }

}
void calculus()
{
    for(i=0;i<=2*n;i=i+2)
    {
        for(j=1;j<=2*n;j=j+2)
        {
            if(((coordonate[j+2]-coordonate[j])/(coordonate[i+2]-coordonate[i]))
               ==
               ((coordonate[j+4]-coordonate[j+2])/(coordonate[i+4]-coordonate[i+2])))
            {
                trapez_cout++;
            }
        }
    }
}
main()
{
    read();
    calculus();
    ofstream trapez_out;
    trapez_out.open("trapez.out");
    trapez_out<<trapez_cout;
    trapez_out.close();
}