source_code: import java.util.*;
  import java.io.*;
  
  public class a {
  	public static void main(String[] args) throws Exception {
  		Scanner sc = new Scanner(System.in);
  		int n = sc.nextInt();
  		int t = sc.nextInt();
  		int[][] xa = new int[n][2];
  		for(int i=0; i<n; ++i) {
  			xa[i][0] = sc.nextInt();
  			xa[i][1] = sc.nextInt();
  		}
  	    Arrays.sort(xa, new Comparator<int[]>(){
              @Override
              public int compare(int[] a0, int[] a1){
                  return a0[0]-a1[0];
              }
          });
  		  int ans=2;
  	        for(int i=0; i<n-1; i++){
  	            int s=(xa[i+1][0]*2-xa[i+1][1])-(xa[i][0]*2+xa[i][1]);
  	            if(s>t*2){
  	                ans+=2;
  	            }else if(s==t*2){
  	                ans++;
  	            }
  	        }
  	        System.out.println(ans+"");
  	}
  }