source_code: import java.io.BufferedReader;
  import static java.lang.Math.*;
  import java.io.File;
  import java.io.FileReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.*;
  
  public class CodeforcesA implements Runnable {
  	public static final String taskname = "A";
  	BufferedReader in;
  	PrintWriter out;
  	StringTokenizer tok;
  
  	public static void main(String[] args) {
  		new Thread(new CodeforcesA()).start();
  	}
  	
  	static class Square implements Comparable<Square>{
  		int x, a;
  		public Square(int x, int a) {
  			this.x = x;
  			this.a = a;
  		}
  		@Override
  		public int compareTo(Square o) {
  			return x - o.x;
  		}
  		
  		int distance(Square a, int t) {
  			double dist = a.x - x - this.a / 2.0 - a.a / 2.0;
  			if(dist > t) return 2;
  			else if(abs(dist - t) < 1e-9) return 1;
  			return 0;
  		}
  		
  		public String toString() {
  			return x + " " + a;
  		}
  	}
  	
  
  	void solve() throws IOException {
  		int n = nextInt(), t = nextInt();
  		Square[] x = new Square[n];
  		for(int i = 0; i < n; ++i) {
  			x[i] = new Square(nextInt(), nextInt());
  		}
  		Arrays.sort(x);
  		long res = 2;
  		for(int i = 0; i < n - 1; ++i) {
  			res += x[i].distance(x[i + 1], t);
  		}
  		out.println(res);
  			
  	}
  
  	@Override
  	public void run() {
  		try {
  			in = new BufferedReader(new InputStreamReader(System.in));
  			//in = new BufferedReader(new FileReader(new File("input.txt")));
  			 out = new PrintWriter(System.out);
  			//out = new PrintWriter(new File("output.txt"));
  			solve();
  			out.flush();
  			out.close();
  			in.close();
  		} catch (IOException e) {
  			// TODO Auto-generated catch block
  			e.printStackTrace();
  		}
  
  	}
  
  	String nextLine() throws IOException {
  		tok = null;
  		return in.readLine();
  	}
  
  	double nextDouble() throws IOException {
  		return Double.parseDouble(nextToken());
  	}
  
  	int nextInt() throws IOException {
  		return Integer.parseInt(nextToken());
  	}
  
  	String nextToken() throws IOException {
  		while (tok == null || !tok.hasMoreTokens()) {
  			tok = new StringTokenizer(in.readLine());
  		}
  		return tok.nextToken();
  	}
  
  }
  