#include <bits/stdc++.h>
using namespace std;
int pct(int x) { return __builtin_popcount(x); }
int pct(long long x) { return __builtin_popcountll(x); }
int bit(int x) { return 31 - __builtin_clz(x); }
int bit(long long x) { return 63 - __builtin_clzll(x); }
int cdiv(int a, int b) { return a / b + !(a < 0 || a % b == 0); }
long long cdiv(long long a, long long b) {
  return a / b + !(a < 0 || a % b == 0);
}
int nxt_C(int x) {
  int c = x & -x, r = x + c;
  return (((r ^ x) >> 2) / c) | r;
}
long long nxt_C(long long x) {
  long long c = x & -x, r = x + c;
  return (((r ^ x) >> 2) / c) | r;
}
vector<int> get_bits(int mask) {
  vector<int> bb;
  while (mask) {
    int b = bit(mask);
    bb.push_back(b);
    mask ^= (1 << b);
  }
  reverse(bb.begin(), bb.end());
  return bb;
}
int get_mask(vector<int> v) {
  int mask = 0;
  for (int x : v) {
    mask ^= (1 << x);
  }
  return mask;
}
template <typename T>
void uniq(vector<T> &v) {
  sort(v.begin(), v.end());
  v.resize(unique(v.begin(), v.end()) - v.begin());
}
template <typename T>
void leftShift(vector<T> &v, long long k) {
  k %= (int)v.size();
  if (k < 0) k += (int)v.size();
  rotate(v.begin(), v.begin() + k, v.end());
}
template <typename T>
void rightShift(vector<T> &v, long long k) {
  leftShift(v, (int)v.size() - k);
}
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
long long rand(long long l, long long r) {
  uniform_int_distribution<long long> uid(l, r);
  return uid(rng);
}
void pr() {}
void sc() {}
template <typename Head, typename... Tail>
void pr(Head H, Tail... T) {
  cout << H << " ";
  pr(T...);
}
template <typename Head, typename... Tail>
void sc(Head &H, Tail &...T) {
  cin >> H;
  sc(T...);
}
string to_string(__int128 x) {
  string s = "";
  bool neg = 0;
  if (x < 0) {
    s += "-";
    neg = 1;
    x = -x;
  }
  if (!x) s += '0';
  while (x) {
    int rem = x % 10;
    s += to_string(rem);
    x /= 10;
  }
  reverse(s.begin() + neg, s.end());
  return s;
}
const int mod = 1e9 + 7;
int pwr(int a, int b) {
  int ans = 1;
  while (b) {
    if (b & 1) ans = (ans * 1LL * a) % mod;
    a = (a * 1LL * a) % mod;
    b >>= 1;
  }
  return ans;
}
const int N = 1e5 + 5;
pair<long long, long long> p[N];
map<long long, long long> z;
long long cross(pair<long long, long long> a, pair<long long, long long> b) {
  return a.first * 1LL * b.second - a.second * 1LL * b.first;
}
pair<long long, long long> operator-(pair<long long, long long> a,
                                     pair<long long, long long> b) {
  return {a.first - b.first, a.second - b.second};
}
bool bad(pair<long long, long long> a, pair<long long, long long> b,
         pair<long long, long long> c) {
  return cross(b - a, c - a) >= 0;
}
void solve() {
  int n;
  sc(n);
  for (int i = 1; i <= n; i++) {
    sc(p[i].first, p[i].second);
    p[i].second -= p[i].first * p[i].first;
    if (!z.count(p[i].first))
      z[p[i].first] = p[i].second;
    else
      z[p[i].first] = max(z[p[i].first], p[i].second);
  }
  n = 0;
  for (auto x : z) {
    p[++n] = x;
  }
  vector<pair<long long, long long> > v;
  for (int i = 1; i <= n; i++) {
    while ((int)v.size() > 1 && bad(v[(int)v.size() - 2], v.back(), p[i]))
      v.pop_back();
    v.push_back(p[i]);
  }
  42;
  cout << (int)v.size() - 1;
}
signed main() {
  ios ::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t;
  t = 1;
  for (int tt = 1; tt <= t; tt++) {
    solve();
  }
  return 0;
}
