#include <bits/stdc++.h>
using namespace std;
struct Seg {
  int l, r;
  bool operator<(const Seg a) const {
    if (a.r != r) return r < a.r;
    return l < a.l;
  }
} s[200005];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    int a, b;
    scanf("%d%d", &a, &b);
    s[i].l = a - b;
    s[i].r = a + b;
  }
  sort(s + 1, s + n + 1);
  int rr = -0x7fffffff, ss = 0;
  for (int i = 1; i <= n; i++) {
    if (s[i].l >= rr) rr = s[i].r, ss++;
  }
  cout << ss;
  return 0;
}
