#include <iostream>
#include <vector>
#include <algorithm>
#include <math.h>
using namespace std;
typedef long long int ll;

int n;
ll x[4040],y[4040];

int main(){
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	long double pi=4*atan(1);
	cin >> n;
	vector<long double> v;
	for(int i=0;i<n;i++){
		cin >> x[i] >> y[i];
		ll g=__gcd(abs(x[i]),abs(y[i]));
		if(g==0){
			i--;
			n--;
			break;
		}
		v.push_back(atan2(y[i],x[i]));
		v.push_back(atan2(y[i],x[i])+2*pi);
		v.push_back(atan2(y[i],x[i])+4*pi);
	}
	sort(v.begin(),v.end());
	ll ret=0;
	for(int i=0;i<n;i++){
		int j=i;
		while(v[j]-v[i]<=pi+1e-12)j++;
		int y=j;
		for(int x=i+1;x<j;x++){
			if(v[i]!=v[x]){
				if(v[x]-v[i]>=pi-1e-12)break;
				while(v[y]-v[x]<pi-1e-12)y++;
				ret+=(y-j);
			}
		}
	}
	cout << ret/3 << endl;
}