#include <bits/stdc++.h>
using namespace std;
pair<long long, pair<long long, long long> > arr[1000006];
int main() {
  int n;
  long long x, w;
  cin >> n;
  pair<long long, long long> tm;
  for (int i = 0; i < n; i++) {
    cin >> x >> w;
    arr[i].first = x - w;
    arr[i].second = make_pair(x, w);
  }
  sort(arr, arr + n);
  long long ans = 1;
  long long ta = arr[n - 1].first;
  for (int i = n - 2; i >= 0; i--) {
    tm = arr[i].second;
    if (tm.first + tm.second <= ta) {
      ans++;
      ta = arr[i].first;
    }
  }
  cout << ans << endl;
}
