#include <bits/stdc++.h>
using namespace std;
template <typename T>
void chkMax(T &x, T y) {
  if (y > x) x = y;
}
template <typename T>
void chkMin(T &x, T y) {
  if (y < x) x = y;
}
template <typename T>
void inline read(T &x) {
  int f = 1;
  x = 0;
  char s = getchar();
  while (s < '0' || s > '9') {
    if (s == '-') f = -1;
    s = getchar();
  }
  while (s <= '9' && s >= '0') x = x * 10 + (s ^ 48), s = getchar();
  x *= f;
}
template <typename T>
void print(T x) {
  if (x < 0) {
    putchar('-');
    print(-x);
    return;
  }
  if (x >= 10) print(x / 10);
  putchar((x % 10) + '0');
}
const int N = 1e5 + 5;
pair<long long, long long> operator-(pair<long long, long long> x,
                                     pair<long long, long long> y) {
  return make_pair(x.first - y.first, x.second - y.second);
}
long long inline cross(pair<long long, long long> a,
                       pair<long long, long long> b) {
  return a.first * b.second - a.second * b.first;
}
bool inline isOn(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;
}
int n, s[N], top;
pair<long long, long long> a[N];
int main() {
  read(n);
  for (int i = 1; i <= n; i++)
    read(a[i].first), read(a[i].second), a[i].second -= a[i].first * a[i].first;
  sort(a + 1, a + 1 + n);
  for (int i = 1; i <= n; i++) {
    while (top > 1 && isOn(a[s[top - 1]], a[s[top]], a[i])) top--;
    s[++top] = i;
  }
  int ans = 0;
  for (int i = 1; i < top; i++)
    if (a[s[i]].first != a[s[i + 1]].first) ans++;
  print(ans);
  return 0;
}
