#include <bits/stdc++.h>
using namespace std;
#pragma warning(disable : 4996)
const int INF = 2e9 + 5;
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  vector<pair<int, int>> v;
  for (int i = 0; i < n; i++) {
    int x, w;
    cin >> x >> w;
    v.push_back({x - w, x + w});
  }
  sort(v.begin(), v.end());
  int mn = INF, last = INF, ans = 0;
  for (int i = n - 1; i >= 0; i--) {
    if (v[i].second < mn && last >= v[i].second) {
      ans++;
      last = v[i].first;
    }
    mn = min(mn, v[i].second);
  }
  cout << ans;
  return 0;
}
