#include <bits/stdc++.h>
std::mt19937 rng(
    (int)std::chrono::steady_clock::now().time_since_epoch().count());
struct PT {
  long long x, y;
  PT(long long xx = 0, long long yy = 0) : x(xx), y(yy) {}
  PT operator+(const PT &p) const { return PT(x + p.x, y + p.y); }
  PT operator-(const PT &p) const { return PT(x - p.x, y - p.y); }
  PT operator*(long long c) const { return PT(x * c, y * c); }
  long long operator*(const PT &p) const { return x * p.x + y * p.y; }
  long long operator%(const PT &p) const { return x * p.y - y * p.x; }
};
std::vector<PT> ConvexHull(std::vector<PT> pts) {
  if (pts.size() <= 2) return pts;
  std::sort(pts.begin(), pts.end(), [](PT a, PT b) -> bool {
    return a.x != b.x ? a.x < b.x : a.y < b.y;
  });
  std::vector<PT> ans(2 * pts.size());
  int s = 0;
  for (int i = 0; i < pts.size(); i++) {
    while (s > 1 && (pts[i] - ans[s - 2]) % (ans[s - 1] - ans[s - 2]) >= 0) {
      s--;
    }
    ans[s++] = pts[i];
  }
  ans.resize(s);
  while (ans.size() > 2 && ans[s - 1].x == ans[s - 2].x) {
    ans.pop_back();
    s--;
  }
  return ans;
}
int main() {
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(NULL);
  int n;
  std::cin >> n;
  std::vector<PT> hull(n);
  for (int i = 0; i < n; i++) {
    std::cin >> hull[i].x >> hull[i].y;
    hull[i].y -= hull[i].x * hull[i].x;
    hull[i].y = -hull[i].y;
  }
  hull = ConvexHull(hull);
  for (auto p : hull) {
  }
  int ans = (int)hull.size() - 1;
  if (hull.size() >= 2 && hull[0].x == hull[1].x) ans--;
  std::cout << ans << '\n';
}
