#include <bits/stdc++.h>
using namespace std;
using db = long double;
using ll = long long;
using pl = pair<ll, ll>;
using pi = pair<int, int>;
#define vt vector
#define f first
#define s second
#define pb push_back
#define all(x) x.begin(), x.end()
#define size(x) ((int) (x).size())
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define F0R(i, b) FOR (i, 0, b)
#define endl '\n'
const ll INF = 1e18;
const int inf = 1e9;
template<typename Tuple, size_t... Is>
void print_tuple(const Tuple& t, index_sequence<Is...>) {
((cerr << (Is == 0 ? "{" : ", ") << get<Is>(t)), ...);
cerr << "}";
}
template<typename... Args>
ostream& operator<<(ostream& os, const tuple<Args...>& t) {
print_tuple(t, index_sequence_for<Args...>{});
return os;
}
ostream& operator<<(ostream& os, string& s) {
for (char c : s) os << c;
return os;
}
template<template<typename> class Container, typename T>
ostream& operator<<(ostream& os, Container<T> o) {
os << "{";
int g = size(o);
for (auto i : o) os << i << ((--g) == 0 ? "" : ", ");
os << "}";
return os;
}
template<typename T, typename V>
ostream& operator<<(ostream& os, const pair<T, V> p) {
os << "{" << p.f << ", " << p.s << "}";
return os;
}
template <typename T, typename... V>
void printer(const char *names, T &&head, V &&...tail) {
int i = 0;
while (names[i] != '\0' && names[i] != ',') i++;
constexpr bool is_str = is_same_v<decay_t<T>, const char*>;
if constexpr (is_str) cerr << head; // ignore directly passed strings
else cerr.write(names, i) << " = " << head;
if constexpr (sizeof...(tail)) cerr << (is_str ? "" : ","), printer(names + i + 1, tail...);
else cerr << endl;
}
#ifdef LOCAL
#define dbg(...) std::cerr << __LINE__ << ": ", printer(#__VA_ARGS__, __VA_ARGS__)
#else
#define dbg(x...)
#define cerr if (0) std::cerr
#endif
bool covers(pl a, pl b) {
return abs(a.f - b.f) <= a.s - b.s;
}
main() {
cin.tie(0)->sync_with_stdio(0);
int n; cin >> n;
vt<pl> stk;
F0R (i, n) {
ll x, y; cin >> x >> y;
while (size(stk) && covers({x, y}, stk.back())) {
stk.pop_back();
}
if (size(stk) && covers(stk.back(), {x, y})) continue;
stk.pb({x, y});
}
cout << size(stk) << endl;
}
