#include <bits/stdc++.h>
using namespace std;
const int INF = 2e9;
const long long LINF = 2e16;
const int magic = 348;
const int MOD = 1e9 + 7;
const double eps = 1e-14;
const double pi = acos(-1);
template <typename T>
inline void Get(T &first) {
  bool f;
  char ch;
  T res;
  while (!isdigit(ch = getchar()) && ch != '-') {
  }
  if (ch == '-')
    f = false, res = 0;
  else
    f = true, res = ch - '0';
  while (isdigit(ch = getchar())) res = res * 10 + ch - '0';
  first = (f ? res : (-res));
}
template <typename T1, typename... T2>
inline void Get(T1 &first, T2 &...second) {
  Get(first);
  Get(second...);
}
struct fastio {
  static const int S = 1e7;
  char rbuf[S + 48], wbuf[S + 48];
  int rpos, wpos, len;
  fastio() { rpos = len = wpos = 0; }
  inline char Getchar() {
    if (rpos == len) rpos = 0, len = fread(rbuf, 1, S, stdin);
    if (!len) return EOF;
    return rbuf[rpos++];
  }
  template <class T>
  inline void Get(T &first) {
    char ch;
    bool f;
    T res;
    while (!isdigit(ch = Getchar()) && ch != '-') {
    }
    if (ch == '-')
      f = false, res = 0;
    else
      f = true, res = ch - '0';
    while (isdigit(ch = Getchar())) res = res * 10 + ch - '0';
    first = (f ? res : -res);
  }
  template <typename T1, typename... T2>
  inline void Get(T1 &first, T2 &...second) {
    Get(first);
    Get(second...);
  }
  inline void getstring(char *s) {
    char ch;
    while ((ch = Getchar()) <= 32) {
    }
    for (; ch > 32; ch = Getchar()) *s++ = ch;
    *s = '\0';
  }
  inline void flush() {
    fwrite(wbuf, 1, wpos, stdout);
    fflush(stdout);
    wpos = 0;
  }
  inline void Writechar(char ch) {
    if (wpos == S) flush();
    wbuf[wpos++] = ch;
  }
  template <class T>
  inline void Print(T first, char ch) {
    char s[20];
    int pt = 0;
    if (first == 0)
      s[++pt] = '0';
    else {
      if (first < 0) Writechar('-'), first = -first;
      while (first) s[++pt] = '0' + first % 10, first /= 10;
    }
    while (pt) Writechar(s[pt--]);
    Writechar(ch);
  }
  inline void printstring(char *s) {
    int pt = 1;
    while (s[pt] != '\0') Writechar(s[pt++]);
  }
} io;
template <typename T>
inline void check_max(T &first, T cmp) {
  first = max(first, cmp);
}
template <typename T>
inline void check_min(T &first, T cmp) {
  first = min(first, cmp);
}
template <typename T>
inline T myabs(T first) {
  return first >= 0 ? first : -first;
}
template <typename T>
inline T gcd(T first, T second) {
  return second == 0 ? first : gcd(second, first % second);
}
inline int add(int first) {
  if (first >= MOD) first -= MOD;
  return first;
}
inline int add(int first, int MO) {
  if (first >= MO) first -= MO;
  return first;
}
inline int sub(int first) {
  if (first < 0) first += MOD;
  return first;
}
inline int sub(int first, int MO) {
  if (first < 0) first += MO;
  return first;
}
inline void Add(int &first, int second) { first = add(first + second); }
inline void Add(int &first, int second, int MO) {
  first = add(first + second, MO);
}
inline void Sub(int &first, int second) { first = sub(first - second); }
inline void Sub(int &first, int second, int MO) {
  first = sub(first - second, MO);
}
template <typename T>
inline int quick_pow(int first, T second) {
  int res = 1;
  while (second) {
    if (second & 1) res = 1ll * res * first % MOD;
    first = 1ll * first * first % MOD;
    second >>= 1;
  }
  return res;
}
template <typename T>
inline int quick_pow(int first, T second, int MO) {
  int res = 1;
  while (second) {
    if (second & 1) res = 1ll * res * first % MO;
    first = 1ll * first * first % MO;
    second >>= 1;
  }
  return res;
}
const int MAXN = 1e5;
int n;
inline bool islarger(double first, double second) {
  return first - second > eps;
}
inline bool issmaller(double first, double second) {
  return first - second < -eps;
}
inline bool isequal(double first, double second) {
  return !islarger(first, second) && !issmaller(first, second);
}
struct Vector {
  double first, second;
  Vector() {}
  inline Vector(double _x, double _y) {
    first = _x;
    second = _y;
  }
  inline Vector operator+(Vector other) {
    return Vector(first + other.first, second + other.second);
  }
  inline Vector operator-(Vector other) {
    return Vector(first - other.first, second - other.second);
  }
  inline bool operator<(const Vector &other) const {
    if (!isequal(first, other.first)) return issmaller(first, other.first);
    return islarger(second, other.second);
  }
  inline void print() { cout << int(first) << ' ' << int(second) << endl; }
} a[MAXN + 48];
int atot;
inline double query_k(Vector first, Vector second) {
  if (isequal(first.first, second.first))
    return islarger(second.second, first.second) ? double(LINF) : double(-LINF);
  return (second.second - first.second) / (second.first - first.first);
}
Vector conv[MAXN + 48];
int tot = 0;
inline void convex_hull() {
  for (register int i = 1; i <= n; i++) {
    if (atot && isequal(a[atot].first, a[i].first)) continue;
    a[++atot] = a[i];
  }
  for (register int i = 1; i <= atot; i++) {
    while (tot >= 2 && !islarger(query_k(conv[tot - 1], conv[tot]),
                                 query_k(conv[tot], a[i])))
      tot--;
    conv[++tot] = a[i];
  }
}
int main() {
  Get(n);
  for (register int i = 1; i <= n; i++)
    Get(a[i].first, a[i].second), a[i].second -= a[i].first * a[i].first;
  sort(a + 1, a + n + 1);
  convex_hull();
  printf("%d\n", tot - 1);
  io.flush();
  return 0;
}
