#include<iostream>
#include<algorithm>
using namespace std;
typedef long long ll;
ll inf = 1000000000;
typedef pair<ll, ll> P;
P p[100005];
int main() {
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		ll x, l;
		cin >> x >> l;
		p[i] = make_pair(x + l, x - l);
	}
	sort(p, p + n);
	ll ans = 0;
	ll kai = -inf;
	for (int i = 0; i < n; i++) {
		if (kai > p[i].second)continue;
		ans++;
		kai = p[i].first;
	
	}
	cout << ans << endl;
}
