import java.io.*;
import java.util.*;
public class mountainView{
  
  public static int solve(){
    int maxRight=mountain.get(0).right;
    int count=1;
    for(int i=1;i<n;i++){
      if(mountain.get(i).right>maxRight){
        maxRight=mountain.get(i).right;
        count++;
      }
    }
    return count;
  }
  
  static int n;
  static ArrayList<Base> mountain=new ArrayList<>();
  public static void main (String[] args)throws IOException{
    BufferedReader bf = new BufferedReader(new FileReader("mountains.in"));
    PrintWriter pr = new PrintWriter(new FileWriter("mountains.out"));
    n=Integer.parseInt(bf.readLine());
    for(int i=0;i<n;i++){
      StringTokenizer st = new StringTokenizer(bf.readLine());
      int x=Integer.parseInt(st.nextToken());
      int y=Integer.parseInt(st.nextToken());
      mountain.add(new Base(x-y,x+y));
    }
    Collections.sort(mountain);
//    System.out.println(mountain);
//    System.out.println(solve());
    pr.println(solve());
    pr.close();
  }
}
class Base implements Comparable<Base>{
  int left;
  int right;
  public Base(int l,int r){
    left=l;
    right=r;
  }
  public int compareTo(Base b){
      if(this.left<b.left) return -1;
    else if(this.left>b.left) return 1;
    else if(this.right<b.right) return 1;
    else if(this.right>b.right) return -1;
    return 0;
  }
  public String toString(){
    return "("+left+","+right+")";
  }
}