#include <bits/stdc++.h>
using namespace std;
typedef long double ld;
const long double PI =
    3.141592653589793238462643383279502884197169399375105820974944;
long long mod = 1e9 + 7;
const long long inf = 1e18;
const long long maxn = 3e5 + 5;
void solve() {
  long long n;
  cin >> n;
  vector<pair<long long, long long>> v(n), h;
  for (long long i = 0; i < n; i++) {
    cin >> v[i].first >> v[i].second;
    h.push_back({v[i].first + v[i].second, i});
  }
  sort((h).begin(), (h).end());
  long long ans = 1, pt = 0;
  for (long long i = 1; i < n; i++) {
    if (v[h[i].second].first - v[h[i].second].second >= h[pt].first) {
      pt = i;
      ++ans;
    }
  }
  cout << ans;
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long tc = 1;
  while (tc--) {
    solve();
    cout << '\n';
  }
  return 0;
}
