// Made by ordinary newbie
#pragma region setup
#include <bits/stdc++.h>
#include <random>
#include <chrono>
using namespace std;
// variables
#define int long long
using ld = long double;
using ll = long long;
using ull = unsigned long long;
template<typename T>
using min_heap = priority_queue<T, vector<T>, greater<T>>;
// bitwise operations
#define cnt_bit(n) __builtin_popcountll(n)
#define low_bit(n) ((n) & (-(n)))
#define bit(n, i) (((n) >> (i)) & 1)
#define set_bit(n, i) ((n) | (1ll << (i)))
#define reset_bit(n, i) ((n) & ~(1ll << (i)))
#define flip_bit(n, i) ((n) ^ (1ll << (i)))
// math
#define sqr(n) ((n) * (n))
int log2_floor(ull n) {
return n ? __builtin_clzll(1) - __builtin_clzll(n) : -1;
}
const ll INF = 1e18;
// utils
#define len(x) (int) x.size()
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
template <typename T>
istream& operator>>(istream& is, vector<T>& v) {
for(auto& el : v) {
is >> el;
}
return is;
}
template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
for (int i = 0; i < len(v); i++) {
if (i) os << ' ';
os << v[i];
}
return os;
}
template<class... Args>
auto create(size_t n, Args&&... args) {
if constexpr(sizeof...(args) == 1) {
return vector(n, args...);
}
else {
return vector(n, create(args...));
}
}
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
size_t operator()(pair<int, int> x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x.first + FIXED_RANDOM) ^ splitmix64(x.second + FIXED_RANDOM);
}
};
template<typename T, typename U>
bool chmin(T& a, const U b) {
if (b < a) {
a = b;
return true;
}
return false;
}
template<typename T, typename U>
bool chmax(T& a, const U b) {
if (b > a) {
a = b;
return true;
}
return false;
}
template<typename T>
void compress(vector<T>& v) {
int n = len(v);
vector<pair<T, int>> u(n);
for (int i = 0; i < n; i++) {
u[i] = {v[i], i};
}
sort(all(u));
int curr = 0;
for (int i = 0; i < n; i++) {
if (i != 0 && u[i].first != u[i - 1].first) curr++;
v[u[i].second] = curr;
}
}
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
#pragma endregion
void solve() {
int n;
cin >> n;
vector<pair<int, int>> a(n);
for (int i = 0; i < n; i++) {
int x, y;
cin >> x >> y;
a[i] = {x - y, x + y};
}
int mx = -INF;
sort(all(a), [] (pair<int, int> a, pair<int, int> b) {
if (a.first != b.first) {
return a.first < b.first;
}
return a.second > b.second;
});
int ans = 0;
for (auto [x, y] : a) {
if (chmax(mx, y)) {
ans++;
}
}
cout << ans << '\n';
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int tt = 1;
//cin >> tt;
for (int i = 1; i <= tt; i++) {
solve();
}
}
