#include <bits/stdc++.h>
using namespace std;
pair<long long, long long> line[100005], mas[100005];
int tail = 0;
long double inter(pair<long long, long long> L1,
                  pair<long long, long long> L2) {
  return 1.0 * (L2.second - L1.second) / (L1.first - L2.first);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    long long first, second;
    cin >> first >> second;
    line[i] = make_pair(-first, second - first * first);
  }
  sort(line + 1, line + n + 1);
  mas[1] = line[1];
  tail = 1;
  for (int i = 1; i <= n; i++) {
    if (mas[tail].first == line[i].first) {
      if (line[i].second <= mas[tail].second) continue;
      tail--;
    }
    while (tail > 1) {
      pair<long long, long long> L1 = mas[tail];
      pair<long long, long long> L2 = mas[tail - 1];
      tail--;
      if (inter(L2, L1) < inter(L1, line[i])) {
        tail++;
        break;
      }
    }
    tail++;
    mas[tail] = line[i];
  }
  cout << tail - 1;
  return 0;
}
