source_code: import java.util.*;
  
  public class a {
  	public static void main(String[] args) {
  		Scanner in = new Scanner(System.in);
  		int n = in.nextInt();
  		double w = in.nextDouble();
  		int tot = 2;
  		Interval[] houses = new Interval[n];
  		for(int i=0; i<n; i++) {
  			double center = in.nextDouble();
  			double wid = in.nextDouble();
  			houses[i] = new Interval(center-wid/2,center+wid/2);
  		}
  		Arrays.sort(houses);
  		for(int i=1; i<n; i++) {
  			double dist = houses[i].s - houses[i-1].e;
  			if(dist+1e-6 >= w) {
  				tot+=2;
  				if(Math.abs(w-dist) < 1e-6)
  					tot--;
  			}
  		}
  		System.out.println(tot);
  	}
  }
  class Interval implements Comparable<Interval> {
  	double s, e;
  	Interval(double a, double b) {
  		s=a;
  		e=b;
  	}
  	public int compareTo(Interval i) {
  		return (int)Math.signum(s-i.s);
  	}
  }
  