#include <bits/stdc++.h>
using namespace std;
const int maxn = 200000 + 10;
struct Point {
  int x, w;
};
bool cmp(Point& a1, Point& a2) { return a1.x + a1.w < a2.x + a2.w; }
Point s[maxn];
int n;
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d %d", &s[i].x, &s[i].w);
  }
  sort(s + 1, s + 1 + n, cmp);
  int ans = 1, la = 1;
  for (int i = 2; i <= n; i++) {
    if (s[i].x - s[i].w >= s[la].x + s[la].w) {
      la = i;
      ans++;
    }
  }
  cout << ans << endl;
  return 0;
}
