#include <bits/stdc++.h>
using namespace std;
class seg {
 public:
  long long x, w;
};
bool comp(const seg& first, const seg& second) {
  return first.x + first.w < second.x + second.w;
}
int main(void) {
  long long n, x, w, xi, wi;
  cin >> n;
  seg segments[n];
  for (long long i = 0; i < n; i++) {
    cin >> segments[i].x >> segments[i].w;
  }
  sort(segments, segments + n, comp);
  long long j = -1;
  long long ans = 0;
  for (long long i = 0; i < n; i++) {
    if (j == -1) {
      ans++;
      j = i;
    } else {
      if (segments[i].x - segments[i].w >= segments[j].x + segments[j].w) {
        j = i;
        ans++;
      }
    }
  }
  cout << ans << endl;
}
