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

int main() {
    ll n;
    cin >> n;
    vector<pair<ll,ll>> p;
    ll x,l;
    for (int i=0;i<n;i++) {
        cin >> x >> l;
        p.push_back(make_pair(x+l,x-l));
    }
    sort(p.begin(),p.end());
    ll ans=1;
    ll r=p[0].first;
    for (int i=1;i<n;i++) {
        if (p[i].second>=r) {
            ans++;
            r=p[i].first;
        }
    }
    cout << ans << endl;
}