#include <bits/stdc++.h>
using namespace std;
int N;
pair<int, int> arr[200005];
int main() {
  cin.sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> N;
  for (int i = 1; i <= N; i++) {
    cin >> arr[i].first >> arr[i].second;
    int x = arr[i].first - arr[i].second;
    int y = arr[i].first + arr[i].second;
    arr[i].first = y, arr[i].second = x;
  }
  sort(arr + 1, arr + 1 + N);
  long long lst = -LLONG_MAX / 2, ans = 0;
  for (int i = 1; i <= N; i++) {
    if (arr[i].second >= lst) {
      ans++;
      lst = arr[i].first;
    }
  }
  cout << ans;
}
