import java.util.Random;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.PrintWriter;
import java.io.InputStreamReader;
import java.io.File;

public class Task{
	
	static final boolean readFromFile = false;
	static final String fileInputName = "input.txt",
						fileOutputName = "output.txt";
	
	public static void main(String args[]){
		FileInputStream fileInputStream;
		FileOutputStream fileOutputStream;
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		if (readFromFile){
			try{
				fileInputStream = new FileInputStream(new File(fileInputName));
				fileOutputStream = new FileOutputStream(new File(fileOutputName));
			}catch (FileNotFoundException e){
				throw new RuntimeException(e);
			}
		}
		PrintWriter out = new PrintWriter((readFromFile)?fileOutputStream:outputStream);
		InputReader in  = new InputReader((readFromFile)?fileInputStream:inputStream);
		
		Solver s = new Solver(in, out);
		s.solve();
		
		out.close();
	}
}

class Solver{
	private PrintWriter out;
	private InputReader in;
	
	public void solve(){
		int n = in.nextInt();
		double t = in.nextDouble(),
			a[] = new double[n],
			x[] = new double[n];
		for (int i=0;i<n;i++){
			x[i] = in.nextDouble();
			a[i] = in.nextDouble();
		}
		int ans = 2;
		for (int i=0;i<n-1;i++)
			for (int j=i+1;j<n;j++)
				if (x[j]<x[i]){
					double buf = x[i];x[i]=x[j];x[j]=buf;
					buf = a[i]; a[i]=a[j];a[j]=buf;
				}
		
		for (int i=0;i<n-1;i++){
			if (x[i]+a[i]/2+t<x[i+1]-a[i+1]/2)
				ans += 2;
			if (x[i]+a[i]/2+t==x[i+1]-a[i+1]/2)
				ans++;
		}
		out.println(ans);
	}
	
	Solver(InputReader in, PrintWriter out){
		this.in = in;
		this.out = out;
	}
}

class InputReader{
	StringTokenizer tok;
	BufferedReader buf;
	
	InputReader(InputStream in){
		tok = null;
		buf = new BufferedReader(new InputStreamReader(in));
	}

	InputReader(FileInputStream in){
		tok = null;
		buf = new BufferedReader(new InputStreamReader(in));
	}
	
	public String next(){
		while (tok==null || !tok.hasMoreTokens()){
			try{
				tok = new StringTokenizer(buf.readLine());
			}catch (IOException e){
				throw new RuntimeException(e);
			}
		}
		return tok.nextToken();
	}
	
	public int nextInt(){
		return Integer.parseInt(next());
	}
	public long nextLong(){
		return Long.parseLong(next());
	}
	public double nextDouble(){
		return Double.parseDouble(next());
	}
	public float nextFloat(){
		return Float.parseFloat(next());
	}
	public String nextLine(){
		try{
			return buf.readLine();
		}catch (IOException e){
			return null;
		}
	}
}