#include <bits/stdc++.h>
using namespace std;
int main(){
	int N; cin >> N; 
	pair<long long, long long> R[100010] = {}; 
	for(int i = 0; i < N; i++){
		long long x, l; cin >> x >> l; 
		R[i].first = x + l; R[i].second = x - l; 
	}
	sort(R, R+N); 
	int ans = 0; 
	long long r = -2000000007; 
	for(int i = 0; i < N; i++){
		if(R[i].second >= r){
			ans ++; 
			r = R[i].first; 
		}
	}
	cout << ans << endl; 
}