#include <bits/stdc++.h>
using namespace std;
struct mang {
  int x, y;
} a[200005];
bool cmp(mang t1, mang t2) { return t1.x + t1.y < t2.x + t2.y; }
void input() {
  int i, last, res, n;
  scanf("%d", &n);
  for ((i) = 0; (i) < (n); (i)++) scanf("%d %d", &a[i].x, &a[i].y);
  sort(a, a + n, cmp);
  last = 0;
  res = 1;
  for (i = 1; i < n; i++)
    if (a[last].x + a[last].y <= a[i].x - a[i].y) res++, last = i;
  printf("%d", res);
}
int main() {
  input();
  return 0;
}
