#include <bits/stdc++.h>
using namespace std;
struct Vertice {
  int x, w, l, r;
  bool operator<(const Vertice &A) const { return r < A.r; }
};
int n, now, ans;
Vertice a[200010];
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &a[i].x, &a[i].w);
    a[i].l = a[i].x - a[i].w;
    a[i].r = a[i].x + a[i].w;
  }
  sort(a, a + n);
  ans = 0;
  now = -0x3f3f3f3f;
  for (int i = 0; i < n; i++)
    if (a[i].l >= now) {
      now = a[i].r;
      ans++;
    }
  printf("%d\n", ans);
  return 0;
}
