#include <bits/stdc++.h>
using namespace std;
const long long nmax = 200005;
const int mod = 1e9 + 7;
const int inf = 1e9;
const long double eps = 1e-9;
const long double PI = acos(-1.0);
pair<long long, long long> a[nmax];
pair<long long, long long> r[nmax];
bool cmp(pair<long long, long long> a, pair<long long, long long> b) {
  return a.first + a.second < b.first + b.second;
}
int main() {
  ios_base::sync_with_stdio(0);
  int n;
  cin >> n;
  for (int i = 0; i < n; ++i) {
    cin >> a[i].first >> a[i].second;
  }
  sort(a, a + n, cmp);
  long long ans = 1;
  int st = 0;
  for (int i = 1; i < n; ++i) {
    if (a[i].first - a[i].second >= a[st].first + a[st].second) {
      ans++;
      st = i;
    }
  }
  cout << ans << '\n';
  return 0;
}
