#include <bits/stdc++.h>
using namespace std;
bool cmp(pair<long long int, long long int> a,
         pair<long long int, long long int> b) {
  return a.first + a.second < b.first + b.second;
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int n;
  cin >> n;
  vector<pair<long long int, long long int>> points;
  for (long long int i = 0; i < n; i++) {
    long long int x, w;
    cin >> x >> w;
    points.push_back({x, w});
  }
  sort(points.begin(), points.end(), cmp);
  long long int last = 0;
  long long int ans = 1;
  for (long long int i = 1; i < n; i++) {
    if (points[last].first + points[last].second <=
        points[i].first - points[i].second) {
      last = i;
      ++ans;
    }
  }
  cout << ans << '\n';
  return 0;
}
