#include <bits/stdc++.h>
#pragma GCC optimize(2)
#pragma comment(linker, "/STACK:102400000,102400000")
using namespace std;
const long long mod = 998244353;
const long long INF = 1e9 + 7;
const int base = 131;
const double eps = 0.000001;
const double pi = 3.1415926;
int n;
struct point {
  long long x, y;
  point() {}
  point(long long x, long long y) : x(x), y(y) {}
  friend long long operator*(const point &a, const point &b) {
    return a.y * b.x - a.x * b.y;
  }
  friend point operator-(const point &a, const point &b) {
    return point(a.x - b.x, a.y - b.y);
  }
  bool operator<(const point &a) const {
    if (x == a.x) return y < a.y;
    return x < a.x;
  }
};
vector<point> v, st;
void convex_hull() {
  sort(v.begin(), v.end());
  for (int i = n - 1; i >= 0; i--) {
    v[i] = v[i] - v[0];
  }
  for (int i = 0; i < v.size(); i++) {
    int tot = st.size();
    while (tot > 1 && (v[i] - st[tot - 2]) * (st[tot - 1] - st[tot - 2]) >= 0) {
      tot--;
      st.pop_back();
    }
    st.push_back(v[i]);
  }
}
int main() {
  long long x, y;
  while (~scanf("%d", &n)) {
    v.clear();
    st.clear();
    for (int i = 0; i < n; i++) {
      scanf("%lld%lld", &x, &y);
      v.push_back(point(x, y - x * x));
    }
    convex_hull();
    int ans = 0;
    int sz = st.size();
    for (int i = 0; i < sz - 1; i++) {
      if (st[i].x != st[i + 1].x) ans++;
    }
    printf("%d\n", ans);
  }
  return 0;
}
