#include <bits/stdc++.h>
using namespace std;
using point = complex<long long>;
long long cross(point p, point q) { return (conj(p) * q).imag(); }
long long orient(point p, point q, point r) { return cross(q - p, r - p); }
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  vector<point> points;
  for (int i = 0; i < n; ++i) {
    long long xi, yi;
    cin >> xi >> yi;
    yi -= xi * xi;
    points.emplace_back(xi, yi);
  }
  sort(points.begin(), points.end(), [](point a, point b) {
    return make_tuple(a.real(), a.imag()) < make_tuple(b.real(), b.imag());
  });
  vector<point> hull;
  for (auto i : points) {
    if (!hull.empty() && hull.back().real() == i.real()) {
      hull.pop_back();
    }
    while (hull.size() >= 2u &&
           orient(hull[hull.size() - 2u], hull.back(), i) >= 0) {
      hull.pop_back();
    }
    hull.push_back(i);
  }
  cout << hull.size() - 1u << "\n";
}
