#include <bits/stdc++.h>
using namespace std;
template <typename G1, typename G2 = G1, typename G3 = G1>
struct triple {
  G1 first;
  G2 second;
  G3 T;
};
template <typename T>
T cross(complex<T> a, complex<T> b) {
  return imag(conj(a) * b);
}
template <typename T>
T cross(complex<T> a, complex<T> b, complex<long long> c) {
  return cross(b - a, c - a);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  vector<complex<long long> > v;
  for (int i = 0; i < n; i++) {
    long long x, y;
    cin >> x >> y;
    v.push_back({x, y - x * x});
  }
  sort(v.begin(), v.end(), [](complex<long long> x, complex<long long> y) {
    if (x.real() == y.real()) return x.imag() > y.imag();
    return x.real() < y.real();
  });
  vector<complex<long long> > ch;
  for (int i = 0; i < n; i++) {
    while (ch.size() > 1 && cross(ch.end()[-2], ch.end()[-1], v[i]) >= 0)
      ch.pop_back();
    ch.push_back(v[i]);
  }
  while (ch.size() > 1 && ch.end()[-2].real() == ch.end()[-1].real())
    ch.pop_back();
  cout << ch.size() - 1 << '\n';
  return 0;
}
