#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2e5 + 5;
template <typename T>
void chkmax(T &x, T y) {
  x = max(x, y);
}
template <typename T>
void chkmin(T &x, T y) {
  x = min(x, y);
}
template <typename T>
void read(T &x) {
  x = 0;
  int f = 1;
  char c = getchar();
  for (; !isdigit(c); c = getchar())
    if (c == '-') f = -f;
  for (; isdigit(c); c = getchar()) x = x * 10 + c - '0';
  x *= f;
}
template <typename T>
void write(T x) {
  if (x < 0) x = -x, putchar('-');
  if (x > 9) write(x / 10);
  putchar(x % 10 + '0');
}
template <typename T>
void writeln(T x) {
  write(x);
  puts("");
}
struct point {
  long long x, y;
} a[MAXN];
point operator+(point a, point b) { return (point){a.x + b.x, a.y + b.y}; }
point operator-(point a, point b) { return (point){a.x - b.x, a.y - b.y}; }
point operator*(point a, int b) { return (point){a.x * b, a.y * b}; }
long long operator*(point a, point b) {
  return 1ll * a.x * b.y - 1ll * a.y * b.x;
}
bool operator<(point a, point b) {
  if (a.x == b.x)
    return a.y < b.y;
  else
    return a.x > b.x;
}
int main() {
  int n;
  read(n);
  for (int i = 1; i <= n; i++) {
    long long x, y;
    read(x), read(y);
    a[i] = (point){x, y - x * x};
  }
  sort(a + 1, a + n + 1);
  int top = 1;
  for (int i = 2; i <= n; i++) {
    if (a[top].x == a[i].x) top--;
    while (top >= 2 && (a[top] - a[top - 1]) * (a[i] - a[top - 1]) <= 0) top--;
    a[++top] = a[i];
  }
  printf("%d\n", top - 1);
  return 0;
}
