#include <bits/stdc++.h>
using namespace std;
struct node {
  int x, y;
} a[200005];
int cmp(node a, node b) {
  if (a.y != b.y)
    return a.y < b.y;
  else
    return a.x < b.x;
}
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    int pos;
    int w;
    scanf("%d%d", &pos, &w);
    a[i].x = pos - w;
    a[i].y = pos + w;
  }
  sort(a, a + n, cmp);
  int ans = 1;
  int maxn = a[0].y;
  for (int i = 1; i < n; i++) {
    if (a[i].x >= maxn) {
      maxn = a[i].y;
      ans++;
    }
  }
  printf("%d", ans);
}
