#include <iostream> #include <vector> #include <algorithm> #include <map> #include <queue> using namespace std; typedef long long ll; #define st first #define nd second #define f(a, c, b) for (int a = c; b > a; a++) #define pb push_back #define all(a) a.begin(), a.end() #define sz(a) int(a.size()) const ll DUZO = 1'000'000'000'000'000; vector<vector<pair<ll, ll>>> drzewo; //drzewo[0] - to jest drzewo l drzewo[1] to drzewo r void ustaw(int rd, int ind, pair<ll, ll> val) { drzewo[rd][ind] = val; ind /= 2; while (ind) { drzewo[rd][ind] = min(drzewo[rd][ind *2], drzewo[rd][ind * 2 + 1]); ind /= 2; } } pair<ll, ll> zczytaj(int rd, int l, int r) { pair<ll, ll> ans = {DUZO, -1}; ans = min(ans, drzewo[rd][l]); ans = min(ans, drzewo[rd][r]); while (r > (l + 1)) { if (!(l&1)) ans = min(ans, drzewo[rd][l ^ 1]); if (r&1) ans = min(ans, drzewo[rd][r ^ 1]); l /= 2; r /= 2; } return ans; } void solve() { int n; cin >> n; map<ll, ll> maks_e; f(i, 0, n) { ll x, e; cin >> x >> e; maks_e[x] = max(maks_e[x], e); } n = sz(maks_e); vector<pair<ll, ll>> a; for (pair<ll, ll> ele: maks_e) a.pb(ele); sort(all(a)); vector<int> odw(n, 0); priority_queue<pair<ll, ll>> kolejka; f(i, 0, n) kolejka.push({a[i].nd, i}); ll wnk = 0; int stala = 1; while (n > stala) stala *= 2; drzewo.resize(2, vector<pair<ll, ll>>(2 * (stala + 2))); f(i, 0, n) { drzewo[0][i + stala] = {a[i].nd - a[i].st, i}; drzewo[1][i + stala] = {a[i].nd + a[i].st, i}; } f(i, n, stala) { drzewo[0][i + stala] = {DUZO, -1}; drzewo[1][i + stala] = {DUZO, -1}; } for (int i = stala - 1; i > 0; i--) { f(j, 0, 2) drzewo[j][i] = min(drzewo[j][i * 2], drzewo[j][(i * 2) + 1]); } while (sz(kolejka)) { pair<ll, ll> p1 = kolejka.top(); kolejka.pop(); if (odw[p1.nd]) continue; odw[p1.nd] = 1; wnk++; ll wsp = a[p1.nd].nd - a[p1.nd].st; while (p1.nd) { pair<ll, ll> p2 = zczytaj(0, stala, p1.nd + stala - 1); if (p2.st <= wsp) { odw[p2.nd] = 1; ustaw(0, p2.nd + stala, {DUZO, -1}); } else { break; } } wsp = a[p1.nd].nd + a[p1.nd].st; while (p1.nd < (n - 1)) { pair<ll, ll> p2 = zczytaj(1, stala + p1.nd + 1, n - 1 + stala); if (p2.st <= wsp) { odw[p2.nd] = 1; ustaw(1, p2.nd + stala, {DUZO, -1}); } else { break; } } } cout << wnk << "\n"; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); int q = 1; //cin >> q; while (q--) solve(); return 0; }