#include <bits/stdc++.h>
using namespace std;
int main() {
  cin.sync_with_stdio(0);
  cin.tie(0);
  cin.exceptions(cin.failbit);
  int n;
  cin >> n;
  vector<long long> xs(n);
  vector<long long> ys(n);
  vector<long long> zs(n);
  vector<pair<long long, long long> > pts;
  for (int i = (0); i < (n); i++) {
    cin >> xs[i] >> ys[i];
    zs[i] = ys[i] - xs[i] * xs[i];
    pts.push_back({xs[i], zs[i]});
  }
  sort(pts.begin(), pts.end());
  vector<pair<long long, long long> > chull;
  for (int i = (0); i < (n); i++) {
    pair<long long, long long> p = pts[i];
    if (i < n - 1 && pts[i].first == pts[i + 1].first) continue;
    while ((int)(chull).size() > 1) {
      int csz = (int)(chull).size();
      pair<long long, long long> p2 = chull[csz - 1];
      pair<long long, long long> p1 = chull[csz - 2];
      if ((p.second - p2.second) * (p2.first - p1.first) >=
          (p.first - p2.first) * (p2.second - p1.second)) {
        chull.pop_back();
      } else {
        break;
      }
    }
    chull.push_back(p);
  }
  cout << (int)(chull).size() - 1 << endl;
  return 0;
}
