#include <bits/stdc++.h>
using namespace std;
struct Vertex {
  int id;
  int x, w;
  int sum, dif;
  bool operator<(const Vertex& v) const {
    if (x != v.x) return x < v.x;
    return id < v.id;
  }
};
Vertex V[200004];
const int INF = 2000000000;
int N;
int LIS() {
  if (N == 0) return 0;
  vector<int> tail;
  tail.push_back(0);
  for (int i = 1; i < N; ++i) {
    int d = V[i].dif;
    if (V[tail.back()].sum <= d) {
      tail.push_back(i);
      continue;
    }
    int lo = 0, hi = int(tail.size()) - 1;
    while (lo < hi) {
      int mid = (lo + hi) / 2;
      if (V[tail[mid]].sum <= d)
        lo = mid + 1;
      else
        hi = mid;
    }
    if (V[tail[lo]].sum >= d && V[tail[lo]].sum > V[i].sum) {
      tail[lo] = i;
    }
  }
  return tail.size();
}
int main(int argc, char* argv[]) {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> N;
  for (int i = 0; i < N; ++i) {
    V[i].id = i + 1;
    cin >> V[i].x >> V[i].w;
    V[i].sum = V[i].x + V[i].w;
    V[i].dif = V[i].x - V[i].w;
  }
  sort(V, V + N);
  int res = LIS();
  cout << res << endl;
  return 0;
}
