#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
template <typename T>
using lim = numeric_limits<T>;
template <typename T>
istream& operator>>(istream& is, vector<T>& a) {
  for (T& x : a) {
    is >> x;
  }
  return is;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  vector<int> x(n), w(n);
  for (int i = 0; i < n; i++) {
    cin >> x[i] >> w[i];
  }
  vector<int> I(n);
  iota(I.begin(), I.end(), 0);
  sort(I.begin(), I.end(),
       [&](int i, int j) { return x[i] + w[i] < x[j] + w[j]; });
  int ending = lim<int>::min(), ans = 0;
  for (int i : I) {
    if (x[i] - w[i] >= ending) {
      ans++;
      ending = x[i] + w[i];
    }
  }
  cout << ans << endl;
  return 0;
}
