#include <bits/stdc++.h>
using namespace std;
int n;
pair<long long, long long> a[100005];
bool bad(int u, int v, int t) {
  if (a[t].first == a[v].first) return 1;
  return (a[u].second - a[v].second) * (a[t].first - a[v].first) >=
         (a[v].second - a[t].second) * (a[v].first - a[u].first);
}
vector<int> s;
int main(void) {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n;
  for (int i = 1; i <= n; ++i) {
    long long x, y;
    cin >> x >> y;
    a[i].first = -x;
    a[i].second = y - x * x;
  }
  sort(a + 1, a + n + 1);
  for (int i = 1; i <= n; ++i) {
    while (s.size() > 0 && a[s.back()].first == a[i].first) s.pop_back();
    while (s.size() > 1 && bad(s[s.size() - 2], s[s.size() - 1], i))
      s.pop_back();
    s.push_back(i);
  }
  cout << s.size() - 1 << endl;
  return 0;
}
