#include <bits/stdc++.h>
#define INF 1000000007
using namespace std;

int n;
pair<int,int> a[100010];

signed main()
{
	ios::sync_with_stdio(false);
	cin>>n;
	for(int i=1;i<=n;i++){
		int x,l;
		cin>>x>>l;
		a[i].first=x+l;
		a[i].second=x-l;
	}
	sort(a+1,a+n+1);
	int cnt=0,pre=-INF;
	for(int i=1;i<=n;i++){
		if(a[i].second>=pre){
			cnt++;
			pre=a[i].first;
		}
	}
	cout<<cnt<<endl;
	return 0;
}