#include <fstream>
#include <iomanip>
#include <cmath>
using namespace std;

#define MAX 1005
#define eps 0x3f3f3f3f

ifstream f("trapez.in");
ofstream g("trapez.out");

struct vec
{
    int x,y;
}v[MAX];
long double r[MAX*MAX];
long long N, i , j, nr, cnt;

int main()
{
    g << setprecision(15) << fixed;
    f >> N;
    for ( i = 1; i <= N; i++) f >> v[i].x >> v[i].y;
    for ( i = 1; i <= N; i++)
        for ( j = 1; j <= N; j++)
           if (v[j].x - v[i].x == 0 && v[j].y - v[i].y == 0) r[++cnt] = eps;
           else if (v[j].x - v[i].x == 0) r[++cnt] = eps;
           else r[++cnt] = (long double) (v[j].y - v[i].y) / (v[j].x - v[i].x) ;
    N *= N;
    sort( r + 1, r + N + 1);
    for ( i = 1; i < N && r[i] != eps; )
        if (r[i] == r[i + 3]) nr++, i += 4 ;
        else i++;
    //for (i=1;i<=N;i++) g << r[i]<<"\n";
    g << nr;
    return 0;
}