#include <bits/stdc++.h>
using namespace std;
const long long int mod = 1e9 + 7;
const long long int inf = 1e18;
const long long int N = 1005;
template <typename S, typename T>
ostream& operator<<(ostream& out, pair<S, T> const& p) {
  out << '(' << p.f << ", " << p.s << ')';
  return out;
}
template <typename T>
ostream& operator<<(ostream& out, vector<T> const& v) {
  long long int l = v.size();
  for (long long int i = 0; i < l - 1; i++) out << v[i] << ' ';
  if (l > 0) out << v[l - 1];
  return out;
}
template <typename T>
void trace(const char* name, T&& arg1) {
  cout << name << " : " << arg1 << endl;
}
template <typename T, typename... Args>
void trace(const char* names, T&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  cout.write(names, comma - names) << " : " << arg1 << " | ";
  trace(comma + 1, args...);
}
struct point {
  long long int first, second;
};
bool cmp(const point& a, const point& b) {
  return a.first < b.first or (a.first == b.first and a.second < b.second);
}
bool cw(point& a, point& b, point& c) {
  return a.first * (b.second - c.second) + b.first * (c.second - a.second) +
             c.first * (a.second - b.second) <=
         0;
}
bool ccw(point& a, point& b, point& c) {
  return a.first * (b.second - c.second) + b.first * (c.second - a.second) +
             c.first * (a.second - b.second) >=
         0;
}
void computeConvexHull(vector<point>& v) {
  if (v.size() == 1) return;
  int sz = v.size();
  sort(v.begin(), v.end(), cmp);
  point a = v[0], b = v[sz - 1];
  vector<point> up, down;
  up.push_back(a);
  down.push_back(a);
  for (int i = 1; i < sz; i++) {
    if (i == sz - 1 or cw(a, v[i], b)) {
      int k = up.size();
      while (k >= 2 and !cw(up[k - 2], up[k - 1], v[i])) {
        up.pop_back();
        k--;
      }
      up.push_back(v[i]);
    }
    if (i == sz - 1 or ccw(a, v[i], b)) {
      int k = down.size();
      while (k >= 2 and !ccw(down[k - 2], down[k - 1], v[i])) {
        down.pop_back();
        k--;
      }
      down.push_back(v[i]);
    }
  }
  v.clear();
  for (int i = 0; i < up.size(); ++i) v.push_back(up[i]);
}
vector<point> hull, points;
long long int n;
void solve() {
  long long int n;
  cin >> n;
  hull.resize(n);
  points.resize(n);
  for (int i = 0; i < n; i++) {
    cin >> points[i].first >> points[i].second;
    hull[i].first = points[i].first;
    hull[i].second = points[i].second - points[i].first * points[i].first;
  }
  if (n == 1) {
    cout << 0 << endl;
    return;
  }
  computeConvexHull(hull);
  sort(hull.begin(), hull.end(), cmp);
  long long int ans = 0;
  for (int i = 0; i < hull.size() - 2; i++) {
    point p1 = hull[i];
    point p2 = hull[i + 1];
    point p3 = hull[i + 2];
    if (p1.first == p2.first) {
      ans--;
      continue;
    }
    if ((p1.second - p2.second) * (p2.first - p3.first) ==
        (p2.second - p3.second) * (p1.first - p2.first)) {
      ans--;
    }
  }
  long long int siz = hull.size();
  point p1 = hull[siz - 2];
  point p2 = hull[siz - 1];
  if (p1.first == p2.first) {
    ans--;
  }
  cout << ans + hull.size() - 1 << endl;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cout.precision(50);
  solve();
}
