#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;
int gi() {
  int x = 0, o = 1;
  char ch = getchar();
  while ((ch < '0' || ch > '9') && ch != '-') ch = getchar();
  if (ch == '-') o = -1, ch = getchar();
  while (ch >= '0' && ch <= '9') x = x * 10 + ch - '0', ch = getchar();
  return x * o;
}
int n, tp = 0;
pair<long long, long long> p[N], st[N];
double slope(pair<long long, long long> a, pair<long long, long long> b) {
  return 1.0 * (b.second - a.second) / (b.first - a.first);
}
int main() {
  n = gi();
  for (int i = 1; i <= n; i++) {
    int x = gi(), y = gi();
    p[i] = make_pair(x, y - 1ll * x * x);
  }
  sort(p + 1, p + n + 1,
       [&](const pair<long long, long long> &a,
           const pair<long long, long long> &b) {
         return a.first == b.first ? a.second > b.second : a.first < b.first;
       });
  for (int i = 1; i <= n; i++) {
    if (i != 1 && p[i].first == p[i - 1].first) continue;
    while (tp >= 2 && slope(st[tp - 1], st[tp]) <= slope(st[tp], p[i])) --tp;
    st[++tp] = p[i];
  }
  printf("%d\n", tp - 1);
  return 0;
}
