#include <bits/stdc++.h>
using namespace std;
void show() { cout << '\n'; }
template <typename T, typename... Args>
void show(T a, Args... args) {
  cout << a << " ";
  show(args...);
}
template <typename T>
void show_c(T& a) {
  for (auto& x : a) {
    cout << x << " ";
  }
  cout << endl;
}
int main() {
  int n;
  scanf("%d", &n);
  vector<pair<int, int> > vec;
  int x, w;
  for (int i = 0; i < n; ++i) {
    scanf("%d %d", &x, &w);
    vec.push_back(make_pair(x + w, x - w));
  }
  sort(vec.begin(), vec.end());
  int ans = 0;
  int prv = INT_MIN;
  for (int i = 0; i < n; ++i) {
    if (vec[i].second >= prv) {
      ans++;
      prv = vec[i].first;
    }
  }
  printf("%d\n", ans);
  return 0;
}
