#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long n, x, y;
  cin >> n;
  map<long long, long long> mp;
  for (int i = 0; i < n; i++) {
    cin >> x >> y;
    y -= (x * x);
    if (mp.find(x) != mp.end())
      mp[x] = max(mp[x], y);
    else
      mp[x] = y;
  }
  vector<pair<long long, long long> > pts;
  for (auto p : mp) {
    long long x = p.first, y = p.second;
    while (pts.size() >= 2) {
      long long xx = (pts.back().second - pts[pts.size() - 2].second) *
                     (x - pts.back().first);
      long long yy = (pts.back().first - pts[pts.size() - 2].first) *
                     (y - pts.back().second);
      if (xx <= yy)
        pts.pop_back();
      else
        break;
    }
    pts.push_back(p);
  }
  cout << pts.size() - 1;
  return 0;
}
