#include <bits/stdc++.h>
using namespace std;
int n;
pair<long long, long long> tbl[200001];
int main() {
  ios_base::sync_with_stdio(0);
  cin >> n;
  for (int i = 0; i < n; ++i) {
    long long x, w;
    cin >> x >> w;
    tbl[i] = pair<long long, long long>(x + w, x - w);
  }
  sort(tbl, tbl + n);
  int acc = 1;
  int last = 0;
  for (int i = 1; i < n; ++i) {
    if (tbl[last].first <= tbl[i].second) {
      last = i;
      ++acc;
    }
  }
  cout << acc << endl;
  return 0;
}
