using System;
using System.Linq;//リストの使用
using System.Collections.Generic;
using System.Text;//テキストの高速出力に必要
class Program
{
	static void Main()
	{
		string[] input = Console.ReadLine().Split(' ');
		int n = int.Parse(input[0]);
		int m = int.Parse(input[1]);
    int left = 0;
    int right = m-1;
    bool answer = true;
    int[][] vertexes = new int[n][];
    for(int i = 0; i < n; i++)
    {
      int[] nums = Array.ConvertAll(Console.ReadLine().Split(' '),int.Parse);

      if(nums[0] > m-1-nums[1])
      {
        int swapMemo = nums[0];
        nums[0] = m-1-nums[1];
        nums[1] = m-1-swapMemo;
      }
      
      vertexes[i] = new int[2];
      vertexes[i][0] = nums[0];
      vertexes[i][1] = nums[1];
    }
    Array.Sort(vertexes, (a, b) => a[0].CompareTo(b[0]));

    for(int i = 0; i < n; i++)
    {
      if(vertexes[i][0] >= left) left = vertexes[i][1]+1;
      else if(m-1-vertexes[i][0] <= right)
      {
        right = m-1-vertexes[i][1]-1;
      }else
      {
        answer = false;
        break;
      }
      //Console.WriteLine(left+" "+right);
      if(left-1 > right)
      {
        answer = false;
        break;
      }
      
    }
    
		Console.WriteLine(answer?"YES":"NO");
	}
}