#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
bool blogai(pair<long long, long long> a, pair<long long, long long> b,
            pair<long long, long long> c) {
  a.first -= b.first;
  a.second -= b.second;
  c.first -= b.first;
  c.second -= b.second;
  return (a.first * c.second - a.second * c.first <= 0);
}
int main() {
  ios_base::sync_with_stdio(false);
  int n;
  cin >> n;
  vector<pair<long long, long long>> a(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i].first >> a[i].second;
    a[i].second -= a[i].first * a[i].first;
  }
  sort(a.begin(), a.end());
  vector<pair<long long, long long>> b;
  for (pair<long long, long long> i : a) {
    while (!b.empty() && b.back().first == i.first) b.pop_back();
    while (b.size() >= 2) {
      if (blogai(b[b.size() - 2], b.back(), i))
        b.pop_back();
      else
        break;
    }
    b.push_back(i);
  }
  cout << b.size() - 1 << "\n";
}
