#include <bits/stdc++.h>
using namespace std;
const long long N = 200001;
long long t, x, w, n;
vector<pair<long long, long long>> s;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  long long x[n + 1], w[n + 1];
  for (int i = 0; i < n; i++) {
    cin >> x[i] >> w[i];
    s.push_back({x[i] + w[i], i});
  }
  sort(s.begin(), s.end());
  long long ans = 1, last = s[0].second;
  for (int i = 1; i < n; i++) {
    if (x[s[i].second] - w[s[i].second] >= x[last] + w[last]) {
      ans++;
      last = s[i].second;
    }
  }
  cout << ans;
  return 0;
}
