source_code: import java.util.*;
  public class C15A {
      public static void main(String args[]){
          Scanner sc=new Scanner(System.in);
          int n=sc.nextInt();
          int t=sc.nextInt();
          double nm[][]=new double[n][2];
          int a=0;
          int b=0;
          for(int i=0;i<n;i++){
              a=sc.nextInt();
              b=sc.nextInt();
              nm[i][0]=a-(double)b/2;
              nm[i][1]=a+(double)b/2;
          }
  
  
          Arrays.sort(nm, new ArrayColumnComparator(1));
  
          int sum=0;
          for(int i=0;i<n-1;i++){
              if(nm[i+1][0]-nm[i][1]==t)
                  sum++;
              else if(nm[i+1][0]-nm[i][1]>t){
                  sum+=2;
              }
  
          }
  
          System.out.println(sum+2);
      }
  
  }
  class ArrayColumnComparator implements Comparator {
      private int cm = 0;
      ArrayColumnComparator(int cm) {
          this.cm = cm;
      }
      public int compare(Object o1, Object o2) {
          double[] row1 = (double[])o1;
          double[] row2 = (double[])o2;
          int i;
          if (row1[cm]>row2[cm])
              i=1;
          else if(row1[cm]<row2[cm])
              i=-1;
          else i=0;
          return i;
      }
  }
  