#include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
typedef long long ll;
ll inf = 1000000000;
typedef pair<ll, ll> P;
int main() {
	int n;
	cin >> n;
	vector<P>p(n);
	for (int i = 0; i < n; i++) {
		ll x, l;
		cin >> x >> l;
		p[i] = make_pair(x+l, x-l);
	}
	sort(p.begin(), p.end());
	int cnt = 0;
	ll cur = -inf;
	for (int i = 0; i < n; i++) {
		if (cur > p[i].second)continue;
		cnt++;
		cur = p[i].first;
	}
	cout << cnt << endl;
	return 0;
}