#include <bits/stdc++.h>
namespace chtholly {
char buf[1 << 23], *p1 = buf, *p2 = buf;
inline int read() {
  int x = 0, f = 1;
  char c = getchar();
  for (; !isdigit(c); c = getchar()) f ^= c == '-';
  for (; isdigit(c); c = getchar()) x = (x << 3) + (x << 1) + (c ^ '0');
  return f ? x : -x;
}
template <typename mitsuha>
inline bool read(mitsuha &x) {
  x = 0;
  int f = 1;
  char c = getchar();
  for (; !isdigit(c) && ~c; c = getchar()) f ^= c == '-';
  if (!~c) return 0;
  for (; isdigit(c); c = getchar()) x = (x << 3) + (x << 1) + (c ^ '0');
  return x = f ? x : -x, 1;
}
template <typename mitsuha>
inline int write(mitsuha x) {
  if (!x) return 0 & putchar(48);
  if (x < 0) putchar('-'), x = -x;
  int bit[20], i, p = 0;
  for (; x; x /= 10) bit[++p] = x % 10;
  for (i = p; i; --i) putchar(bit[i] + 48);
  return 0;
}
inline char fuhao() {
  char c = getchar();
  for (; isspace(c); c = getchar())
    ;
  return c;
}
}  // namespace chtholly
using namespace chtholly;
using namespace std;
const int yuzu = 2e5;
typedef long long fuko[yuzu | 10];
pair<long long, long long> p[yuzu | 10], stk[yuzu | 10];
long long cross(pair<long long, long long> a, pair<long long, long long> b) {
  long long x1, x2, y1, y2;
  x1 = a.first, y1 = a.second;
  x2 = b.first, y2 = b.second;
  return x1 * y2 - x2 * y1;
}
int main() {
  long long i, n = read(), x, y;
  for (i = 1; i <= n; ++i) read(x), read(y), p[i] = {x, y - x * x};
  sort(p + 1, p + n + 1,
       [&](pair<long long, long long> a, pair<long long, long long> b) {
         return a.first ^ b.first ? a.first < b.first : a.second > b.second;
       });
  int cnt = 1, top = 0;
  p->first = 1e18;
  for (i = 1; i <= n; ++i) {
    pair<long long, long long> a1, a2;
    if (p[i].first == p[i - 1].first) continue;
    for (; a1 = {stk[top].first - stk[top - 1].first,
                 stk[top].second - stk[top - 1].second},
           a2 = {p[i].first - stk[top].first, p[i].second - stk[top].second},
           cross(a1, a2) >= 0 && top > 1;
         --top)
      ;
    stk[++top] = p[i];
  }
  printf("%d\n", top - 1);
}
