#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  int n, x, w;
  cin >> n;
  pair<long long int, long long int> a[n], temp;
  for (int i = 0; i < n; i++) {
    cin >> x;
    cin >> w;
    a[i].first = x - w;
    a[i].second = x + w;
  }
  sort(a, a + n);
  temp.first = -10000000000;
  temp.second = -10000000000;
  int ans = 0;
  for (int i = 0; i < n; i++) {
    if (temp.second <= a[i].first) {
      temp = a[i];
      ans++;
    } else if (temp.second > a[i].second) {
      temp = a[i];
    }
  }
  cout << ans << endl;
  return 0;
}
