#include <bits/stdc++.h>
using namespace std;
int n, temp;
vector<pair<long long, long long> > pairs;
int pos[200000 + 10], weights[200000 + 10];
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> pos[i] >> weights[i];
    pairs.push_back(pair<long long, long long>(pos[i] + weights[i], i));
  }
  sort(pairs.begin(), pairs.end());
  int ans = 0;
  long long end = -3e9;
  for (int i = 0; i < n; i++) {
    auto curr = pairs[i];
    temp = pos[curr.second] - weights[curr.second];
    if (temp >= end) {
      ans++;
      end = curr.first;
    }
  }
  cout << ans << endl;
}
