source_code: import java.util.*;
  
  public class House {
  	public static void main(String[] args) {
  		Scanner sc = new Scanner(System.in);
  		int n = sc.nextInt();
  		int t = sc.nextInt();
  		ArrayList<HS> list = new ArrayList<HS>();
  
  		for (int i = 0; i < n; i++) {
  			list.add(new HS(sc.nextInt(),sc.nextInt()));
  		}
  		
  		Collections.sort(list);
  		
  		int count = 0;
  		
  		if(n >= 1)
  			count = 2;
  		
  		for(int i = 0; i < list.size() - 1; i++){
  			double d = Math.abs(list.get(i + 1).x - list.get(i).x);
  			d -= ((1.0*list.get(i).a/2.0) + (1.0*list.get(i + 1).a/2.0));
  			if ((d >= t)&& ((d-t) <= 0.00000001)){
  				count++;
  			}
  			else if(d > t){
  				count+= 2;
  			} 
  		}
  		System.out.println(count);
  	}
  }
  
  class HS implements Comparable<HS> {
  	public int x;
  	public int a;
  
  	public HS(int x, int a) {
  		this.x = x;
  		this.a = a;
  	}
  
  	public int compareTo(HS o) {
  		return x - o.x;
  	}
  
  }
  