#include <bits/stdc++.h>
using namespace std;
struct st {
  int l, r;
} f[200005];
int n, k, ans = 1, x, w, now;
bool cmp(st p, st q) {
  if (p.r != q.r)
    return p.r < q.r;
  else
    return p.l < q.l;
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d%d", &x, &w);
    f[i].l = x - w;
    f[i].r = x + w;
  }
  sort(f + 1, f + n + 1, cmp);
  now = f[1].r;
  for (int i = 2; i <= n; i++) {
    if (f[i].l >= now) {
      now = f[i].r;
      ans++;
    }
  }
  printf("%d", ans);
  return 0;
}
