#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 101000;
pair<long long, long long> prs[MAX_N];
long long n, tmpx, tmpy, q[MAX_N], tot;
bool check(int a, int b, int c) {
  long long x1 = prs[b].first - prs[a].first,
            y1 = prs[b].second - prs[a].second;
  long long x2 = prs[c].first - prs[b].first,
            y2 = prs[c].second - prs[b].second;
  return x1 * y2 - x2 * y1 >= 0;
}
int main() {
  scanf("%lld", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%lld%lld", &tmpx, &tmpy);
    prs[i].first = tmpx, prs[i].second = tmpy - tmpx * tmpx;
  }
  sort(prs + 1, prs + 1 + n);
  for (int i = 1; i <= n; i++) {
    while (tot >= 1 && prs[q[tot]].first == prs[i].first) tot--;
    while (tot >= 2 && check(q[tot - 1], q[tot], i)) tot--;
    q[++tot] = i;
  }
  printf("%d", tot - 1);
  return 0;
}
