#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
const int INF = 1e9 + 7;
const ll LINF = 1LL<<61;

int n;

int main(){
	int n;
	ll x,l;
	cin >> n;
	vector<pair<ll,ll>> a(n);
	for (int i = 0; i < n; i++){
		cin >> x >> l;
		a[i].first = x + l;
		a[i].second = x - l;
	}

	sort(a.begin(),a.end());

	ll ans = 0;
	x = -LINF;

	for(int i = 0; i < n; i++){
		if(x <= a[i].second){
			ans++;
			x = a[i].first;
		}
	}
	cout << ans << endl;
	return 0;
}