#include <cstdio>

 #include <cmath>

 #include <iostream>

 #include <algorithm>

 #include <vector>

 using namespace std;

 typedef long long ll;

 const int maxn = 1e5 + ;

 int n;

 struct Point {

     ll x, y;

     Point(){}

     Point(ll x, ll y):x(x), y(y) {}

     friend ll operator * (const Point &a, const Point &b) {

         return a.y * b.x - b.y * a.x;

     }

     friend Point operator - (const Point &a, const Point &b) {

         return Point(a.x - b.x, a.y - b.y);

     }

     bool operator < (const Point &rhs) const {

         if (x != rhs.x)    return x < rhs.x;

         return y < rhs.y;

     }

 };

 vector<Point> v, st;

 void read() {

     cin >> n;

     for (int i = ; i < n; i++) {

         ll x, y;

         cin >> x >> y;

         y = y - x * x;

         v.push_back({x, y});

     }

 }

 void convex() {

     sort(v.begin(), v.end());//按坐标排序

     for (int i = n - ; ~i; --i)

         v[i] = v[i] - v[];

     for (int i = ; i < n; i++) {

         int tot = st.size();

         while (tot >  && (v[i] - st[tot - ]) * (st[tot - ] - st[tot - ]) >= )    tot--, st.pop_back();

         st.push_back(v[i]);

     }

 }

 int main() {

     ios_base::sync_with_stdio();

     cin.tie(), cout.tie();

     read();

     convex();

     int ans = ;

     for (int i = ; i < st.size(); i++)

         if (st[i].x != st[i - ].x)//x相同无法构成二次函数

             ans++;

     cout << ans << endl;

     return ;

 }