#include <bits/stdc++.h>
using namespace std;
bool comp(pair<int, pair<int, int>> a, pair<int, pair<int, int>> b) {
  return a.second.first < b.second.first;
}
int main() {
  int n;
  cin >> n;
  pair<int, pair<int, int>> mp[n];
  for (int i = 0; i < n; i++) {
    int a, b;
    cin >> a >> b;
    mp[i].first = a - b;
    mp[i].second.first = a;
    mp[i].second.second = a + b;
  }
  sort(mp, mp + n, comp);
  int ans = 0;
  for (int i = 0; i < n - 1; i++) {
    if (mp[i].second.second > mp[i + 1].first) ans++, i++;
  }
  cout << n - ans;
}
