#include <bits/stdc++.h>
#define ll long long
using namespace std;
bool comp(pair<ll,ll> a, pair<ll,ll> b) {
if (a.first<b.first) return true;
else if (a.first==b.first) return a.second>b.second;
else return false;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
ll n;
cin >> n;
vector<ll> x(n),e(n);
vector<pair<ll,ll>> a(n);
for (int i=0; i<n; i++) {
cin >> x[i] >> e[i];
a[i] = {x[i]-e[i], x[i]+e[i]};
}
sort(a.begin(), a.end(), comp);
ll curr = a[0].second;
ll res = 1;
for (int i=1; i<n; i++) {
if (a[i].second>curr) {
curr = a[i].second;
res++;
}
}
cout << res;
}
