#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;
}
