#include <bits/stdc++.h>

using namespace std;

using int64 = long long;
const int mod = 1e9 + 7;
// const int mod = 998244353;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;


template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 > &p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in : v) is >> in;
  return is;
}

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}

template< typename F >
struct FixPoint : F {
  FixPoint(F &&f) : F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};

template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}


int main() {
  int N;
  cin >> N;
  int64 p0 = 0, n0 = 0;
  vector< pair< int64, int64 > > P;
  for(int i = 0; i < N; i++) {
    int64 a, b;
    cin >> a >> b;
    if(a != 0 || b != 0) {
      if(b == 0) {
        if(a > 0) ++p0;
        else ++n0;
      } else {
        P.emplace_back(a, b);
      }
    }
  }
  N = (int) P.size();
  sort(begin(P), end(P), [](auto p, auto q) {
    return (p.first * q.first < 0) ^ (p.second * q.first < q.second * p.first);
  });
  int64 pc = 0, nc = 0, pt = 0, nt = 0, ans = 0;
  for(int i = 0, j = 0; i < N; i++) {
    if(P[i].first > 0) {
      ans += nt;
      ans += n0 * nc;
    } else {
      ans += pt;
      ans += p0 * pc;
    }
    if(i + 1 < N && P[i].first * P[i + 1].second != P[i + 1].first * P[i].second) {
      int64 tpc = 0, tnc = 0;
      while(j < i + 1) {
        if(P[j].first > 0) tpc++;
        else tnc++;
        j++;
      }
      nt += tnc * pc;
      pt += tpc * nc;
      pc += tpc;
      nc += tnc;
    }
  }
  cout << ans << endl;
}