#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <chrono>
#define _USE_MATH_DEFINES
#include <cmath>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
using namespace std;

#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()

const int INF = 0x3f3f3f3f;
const long long LINF = 0x3f3f3f3f3f3f3f3fLL;
const long double EPS = 1e-15;
const int MOD = 1000000007;
// const int MOD = 998244353;
const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
// const int dy[] = {1, 1, 0, -1, -1, -1, 0, 1},
//           dx[] = {0, -1, -1, -1, 0, 1, 1, 1};

struct IOSetup {
  IOSetup() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(30);
    cerr << fixed << setprecision(10);
  }
} iosetup;
/*-------------------------------------------------*/
int main() {
  int n; cin >> n;
  vector<int> x, y;
  while (n--) {
    int px, py; cin >> px >> py;
    if (px == 0 && py == 0) continue;
    x.emplace_back(px);
    y.emplace_back(py);
  }
  n = x.size();
  vector<long double> theta(n);
  REP(i, n) {
    theta[i] = atan2l(y[i], x[i]);
    if (theta[i] < 0) theta[i] += 2 * M_PI;
  }
  sort(ALL(theta));
  long long ans = 0;
  while (!theta.empty()) {
    if (theta.front() >= M_PI) break;
    long double border = theta.front() + M_PI;
    int l = upper_bound(ALL(theta), border + EPS) - theta.begin();
    FOR(j, 1, theta.size()) {
      if (theta[j] >= border - EPS) break;
      if (abs(theta.front() - theta[j]) < EPS) continue;
      int r = lower_bound(ALL(theta), theta[j] + M_PI - EPS) - theta.begin();
      ans += r - l;
    }
    theta.erase(theta.begin());
  }
  cout << ans << '\n';
  return 0;
}