#include <bits/stdc++.h>
using namespace std;
struct node {
  int l, r;
} a[200019];
bool cmp(node aa, node bb) { return aa.r < bb.r; }
int main() {
  int n, xi, wi, ans = 0, lastt_r = -2e9;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++)
    scanf("%d%d", &xi, &wi), a[i].l = xi - wi, a[i].r = xi + wi;
  sort(a + 1, a + n + 1, cmp);
  for (int i = 1; i <= n; i++)
    if (a[i].l >= lastt_r) ans++, lastt_r = a[i].r;
  cout << ans << endl;
  return 0;
}
