source_code: import java.io.PrintWriter;
  import java.util.Arrays;
  import java.util.Comparator;
  import java.util.Scanner;
  
  /**
   * 
   */
  
  /**
   * @author burdakovd
   * 
   */
  public class A {
  
  	static class House {
  		int x, a;
  	}
  
  	/**
  	 * @param args
  	 */
  	public static void main(final String[] args) {
  		final Scanner in = new Scanner(System.in);
  		final PrintWriter out = new PrintWriter(System.out);
  
  		try {
  			final int n = in.nextInt();
  			final int t = in.nextInt();
  
  			final House[] h = new House[n];
  			for (int i = 0; i < h.length; ++i) {
  				h[i] = new House();
  				h[i].x = in.nextInt();
  				h[i].a = in.nextInt();
  			}
  
  			Arrays.sort(h, new Comparator<House>() {
  
  				@Override
  				public int compare(final House o1, final House o2) {
  					return Integer.valueOf(o1.x).compareTo(o2.x);
  				}
  			});
  
  			int ans = 2;
  			for (int i = 1; i < n; ++i) {
  				final int dspace = 2 * h[i].x - h[i].a
  						- (2 * h[i - 1].x + h[i - 1].a);
  				if (dspace == 2 * t) {
  					++ans;
  				} else if (dspace > 2 * t) {
  					ans += 2;
  				}
  			}
  
  			out.println(ans);
  
  		} finally {
  			in.close();
  			out.close();
  		}
  	}
  }
  