// ?
#include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
#include<iomanip>
using namespace std;

#define EPS 0.00000001
#define equals(a, b) (fabs(a-b) < EPS)

const long double PI = 2*acos(0);

long double arg(long double x, long double y){
    return (atan2(y, x)>0 ? atan2(y,x) : 2*PI+atan2(y,x)) / PI * 180.0;
}

typedef long long ll;

int main(){
    int n;
    cin >> n;
    vector<long double> v, x(n), y(n);
    for(int i = 0; i < n; i++){
        cin >> x[i] >> y[i];
        v.push_back(arg(x[i], y[i]));
    }
    sort(v.begin(), v.end());
    ll ans = 0;
    for(int i = 0; i < n; i++){
        for(int j = i+1; j < n; j++){
            if(equals(v[i],v[j]) || equals(fabs(v[i]-v[j]),180))    continue;
            long double f = v[i]+180, g = v[j]+180;
            if(f < 360 && g < 360){
                ans += lower_bound(v.begin(),v.end(),g)-upper_bound(v.begin(),v.end(),f);
            }else if(f < 360 && g >= 360){
                long double diff = min(v[j]-v[i], 360-(v[j]-v[i]));
                g -= 360;
                if(equals(g+360-f, diff)){
                    ans += v.end() - upper_bound(v.begin(),v.end(),f);
                    ans += lower_bound(v.begin(),v.end(),g) - v.begin();
                }else{
                    swap(f, g);
                    ans += lower_bound(v.begin(),v.end(),g)-upper_bound(v.begin(),v.end(),f);
                }
            }else if(f >= 360 && g >= 360){
                f -= 360;
                g -= 360;
                ans += lower_bound(v.begin(),v.end(),g)-upper_bound(v.begin(),v.end(),f);
            }
            cerr << i << " " << j << " " << ans << endl;
        }
    }
    cerr << ans << endl;
    cout << ans/3 << endl;
    return 0;
}