#include <bits/stdc++.h>
using namespace std;
const int maxn = 200000 + 100;
struct Node {
  int l, r;
} p[maxn];
int n, x, y;
inline bool cmp(const Node &a, const Node &b) { return a.r < b.r; }
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &x, &y);
    p[i].l = x - y;
    p[i].r = x + y;
  }
  sort(p, p + n, cmp);
  int t = -0x3f3f3f3f;
  int ans = 0;
  for (int i = 0; i < n; i++)
    if (p[i].l >= t) {
      t = p[i].r;
      ans++;
    }
  cout << ans << endl;
  return 0;
}
