#include <bits/stdc++.h>
using namespace std;
const int NUM = 2e5 + 10;
struct node {
  int index, q;
  bool operator<(const node &a) const { return index + q < a.index + a.q; }
} no[NUM];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d%d", &no[i].index, &no[i].q);
  sort(no, no + n);
  int ans = 1, last = 0;
  for (int i = 1; i < n; i++) {
    if (no[i].index - no[i].q >= no[last].index + no[last].q) {
      last = i;
      ans++;
    }
  }
  printf("%d\n", ans);
  return 0;
}
