source_code: import java.io.*;
  import java.util.*;
  
  public class Solution {
  	
  	private BufferedReader in;
  	private PrintWriter out;
  	private StringTokenizer st;
  
  	static class House implements Comparable<House> {
  		int x, a;
  
  		@Override
  		public int compareTo(House o) {
  			return x - o.x;
  		}
  
  		public House(int x, int a) {
  			this.x = x;
  			this.a = a;
  		}
  	}
  	
  	void solve() throws IOException {
  		int n = nextInt();
  		int t = nextInt();
  		House[] hs = new House[n];
  		for (int i = 0; i < n; ++i) {
  			hs[i] = new House(nextInt(), nextInt());
  		}
  		Arrays.sort(hs);
  		int ans = 2;
  		for (int i = 0; i < n - 1; ++i) {
  			if (hs[i].a + hs[i + 1].a + 2 * t < 2 * (hs[i + 1].x - hs[i].x)) {
  				ans += 2;
  			} else if (hs[i].a + hs[i + 1].a + 2 * t == 2 * (hs[i + 1].x - hs[i].x)) {
  				ans++;
  			}
  		}
  		out.println(ans);
  	}
  
  	Solution() throws IOException {
  		in = new BufferedReader(new InputStreamReader(System.in));
  		out = new PrintWriter(System.out);
  		
  		eat("");
  		
  		solve();
  		
  		in.close();
  		out.close();
  	}
  	
  	private void eat(String str) {
  		st = new StringTokenizer(str);
  	}
  	
  	String next() throws IOException {
  		while (!st.hasMoreTokens()) {
  			String line = in.readLine();
  			if (line == null) {
  				return null;
  			}
  			eat(line);
  		}
  		return st.nextToken();
  	}
  	
  	int nextInt() throws IOException {
  		return Integer.parseInt(next());
  	}
  	
  	long nextLong() throws IOException {
  		return Long.parseLong(next());
  	}
  	
  	double nextDouble() throws IOException {
  		return Double.parseDouble(next());
  	}
  
  	public static void main(String[] args) throws IOException {
  		new Solution();
  	}
  }
  