#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e5 + 10;
int n;
struct seg {
  int L, R;
  bool operator<(const seg &p) const {
    if (R == p.R) return L > p.L;
    return R < p.R;
  }
} s[maxn];
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    int x, w;
    scanf("%d%d", &x, &w);
    s[i].L = x - w;
    s[i].R = x + w;
  }
  sort(s + 1, s + 1 + n);
  int ans = 1, last = s[1].R;
  for (int i = 2; i <= n; i++)
    if (s[i].L >= last) {
      ans++;
      last = s[i].R;
    }
  return 0 * printf("%d\n", ans);
}
