/*
* AUTHOR : lo0ker
* Problem : Advertisement 2
* source : https://oj.uz/problem/view/JOI23_ho_t2
*/
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using pii = pair<int, int>;
#define pb push_back
#define all(x) begin(x), end(x)
#define sz(x) (int) (x).size()
const int MOD = 1e9+7;
struct house{
int x, e;
};
bool comp(house a, house b){
return a.x < b.x;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n;
cin >> n;
int x, e;
vector<house> a;
for(int i = 0; i < n; i++){
cin >> x >> e;
a.push_back({x, e});
}
sort(all(a), comp);
priority_queue<pii> pq;
for(int i = 0; i < n; i++){
pq.push({a[i].e, i});
}
vector<bool> isV(n, false);
int ans = 0;
while(!pq.empty()){
auto [ei, i] = pq.top();
pq.pop();
if(isV[i]) continue;
ans++;
for(int j = i-1; j >= 0; j--){
if((a[i].x - a[j].x) <= (ei - a[j].e)){
isV[j] = true;
}
}
for(int j = i+1; j < n; j++){
if((a[j].x - a[i].x) <= (ei - a[j].e)){
isV[j] = true;
}
}
}
cout << ans;
return 0;
}
