#include <fstream>
#include <vector>
#include <algorithm>
#include <cmath>
using namespace std;

ifstream is("trapez.in");
ofstream os("trapez.out");

#define x first
#define y second
#define pair pair<int, int>
#define EPS 0.00000000001
#define INF 0x3f3f3f3f

vector< pair > v;
vector<double> p;
int n, cnt;

double Paralela( pair i , pair j );

int main()
{
    is >> n;
    v.resize( n + 1 );
    for ( int i = 1; i <= n; i++ )
    {
        is >> v[i].x >> v[i].y;
        for ( int j = i - 1; j >= 1; j-- )
            p.push_back( Paralela( v[i], v[j] ) );
    }
    sort( p.begin(), p.end() );
    int s = 0, q;
    for ( int i = 0; i < p.size(); i++ )
    {
        q = i;
        if ( abs( p[i+1] - p[i] ) < EPS ) s++;
        else
        {
            cnt += ( s * ( s + 1 ) ) / 2;
            s = 0;
        }
    }
    cnt += ( s * ( s + 1 ) ) / 2;
    if ( q != p.size() - 1 )
    {
        s = p.size() - q - 1;
        cnt += ( s * ( s + 1 ) ) / 2;
    }

    os << cnt;

    is.close();
    os.close();
    return 0;
}

double Paralela( pair i , pair j )
{
    if ( i.x == j.x ) return INF;
    if ( i.y == j.y ) return 0;
    return 1. * (j.y - i.y) / (j.x - i.x);
}