#include <bits/stdc++.h>
using namespace std;
const long long N = 2e5 + 5, mod = 1e9 + 7, mod1 = 998244353, mod2 = 1e9 + 9,
                inf = 1e18 + 7;
const long long infll = 1e18 + 7;
long long idx1, idx2;
struct pt {
  double x, y;
};
bool cmp(pt a, pt b) { return a.x < b.x || (a.x == b.x && a.y < b.y); }
bool cw(pt a, pt b, pt c) {
  return a.x * (b.y - c.y) + b.x * (c.y - a.y) + c.x * (a.y - b.y) < 0;
}
bool ccw(pt a, pt b, pt c) {
  return a.x * (b.y - c.y) + b.x * (c.y - a.y) + c.x * (a.y - b.y) > 0;
}
void convex_hull(vector<pt>& a) {
  if (a.size() == 1) return;
  sort(a.begin(), a.end(), &cmp);
  pt p1 = a[0], p2 = a.back();
  vector<pt> up, down;
  up.push_back(p1);
  down.push_back(p1);
  for (long long i = 1; i < (long long)a.size(); i++) {
    if (i == a.size() - 1 || cw(p1, a[i], p2)) {
      while (up.size() >= 2 && !cw(up[up.size() - 2], up[up.size() - 1], a[i]))
        up.pop_back();
      up.push_back(a[i]);
    }
    if (i == a.size() - 1 || ccw(p1, a[i], p2)) {
      while (down.size() >= 2 &&
             !ccw(down[down.size() - 2], down[down.size() - 1], a[i]))
        down.pop_back();
      down.push_back(a[i]);
    }
  }
  a.clear();
  for (long long i = 0; i < (long long)up.size(); i++) a.push_back(up[i]);
  for (long long i = down.size() - 2; i > 0; i--) a.push_back(down[i]);
  idx1 = 0;
  idx2 = up.size() - 1;
  while (idx1 + 1 < a.size() && a[idx1 + 1].x == a[idx1].x) idx1++;
}
long long n;
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n;
  vector<pt> a(n);
  for (long long i = 0; i < n; i++) {
    long long x, y;
    cin >> x >> y;
    y -= x * x;
    a[i].x = x;
    a[i].y = y;
  }
  convex_hull(a);
  cout << idx2 - idx1 << '\n';
}
