#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#include "templates/debug.h"
#else
#define debug(...) 0
#endif
#define rep(i, begin, end) for (__typeof(end) i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1 - 2 * ((begin) > (end)))
#define eb emplace_back
#define pb push_back
#define mt make_tuple
#define mp make_pair
#define all(x) (x).begin(), (x).end()
#define SZ(x) (int) x.size()
using ll = long long;
using ull = unsigned ll;
using lll = __int128_t;
using ulll = __uint128_t;
using ld = long double;
using ii = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;
using vii = vector<ii>;
template<typename T> using mx_pq = priority_queue<T>;
template<typename T> using mn_pq = priority_queue<T, vector<T>, greater<T>>;
template<typename T> void cmax(T &a, const T &b) { a = max(a, b); }
template<typename T> void cmin(T &a, const T &b) { a = min(a, b); }
const int INF = 0x3f3f3f3f;
const ll LINF = (ll) 1e18;
const double DINF = 1.0 / 0.0;
const double pi = acos(-1);
const double EPS = 1e-9;
void solve(int current_case);
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int t = 1;
//cin >> t;
for (int q = 1; q <= t; q++) solve(q);
return 0;
}
struct node {
int l, r, val, lazy;
node *left ,*right;
};
node *build(int l, int r) {
return new node{l, r, -INF, -INF, nullptr, nullptr};
}
void propagate(node *cur) {
if (cur == nullptr || cur->lazy == -INF) return;
cmax(cur->val, cur->lazy);
if (cur->l != cur->r) {
if (cur->left == nullptr) cur->left = build(cur->l, (cur->l + cur->r) / 2);
if (cur->right == nullptr) cur->right = build((cur->l + cur->r) / 2 + 1, cur->r);
cmax(cur->left->lazy, cur->lazy);
cmax(cur->right->lazy, cur->lazy);
}
cur->lazy = -INF;
}
int query(node *cur, int l, int r) { // max
if (cur == nullptr) return -INF;
propagate(cur);
if (l > cur->r || r < cur->l) return -INF;
if (l <= cur->l && cur->r <= r) return cur->val;
return max(query(cur->left, l, r), query(cur->right, l, r));
}
void update(node *cur, int l, int r, int val) { // add
propagate(cur);
if (l > cur->r || r < cur->l) return;
if (l <= cur->l && cur->r <= r) {
cmax(cur->lazy, val);
propagate(cur);
return;
}
if (cur->left == nullptr) cur->left = build(cur->l, (cur->l + cur->r) / 2);
if (cur->right == nullptr) cur->right = build((cur->l + cur->r) / 2 + 1, cur->r);
update(cur->left, l, r, val); update(cur->right, l, r, val);
cur->val = max(cur->left->val, cur->right->val);
}
void solve(int current_case) {
int n; cin >> n;
vi x(n), e(n);
vii v(n);
rep(i, 0, n) cin >> x[i] >> e[i], v[i] = {e[i], x[i]};
int mx = *max_element(all(x));
sort(v.rbegin(), v.rend());
node *root_l = build(1, mx), *root_r = build(1, mx);
int ans = 0;
for (auto &p : v) {
if (query(root_l, p.second, p.second) >= p.first - p.second || query(root_r, p.second, p.second) >= p.first + p.second) continue;
ans++;
update(root_l, 1, p.second, p.first - p.second);
update(root_r, p.second, mx, p.first + p.second);
}
cout << ans << '\n';
}
