n,m = gets.split.map(&:to_i)
wall = Array.new(m+1,0)
n.times do 
    l,r = gets.split.map(&:to_i)
    wall[l] += 1
    wall[r+1] -= 1

    wall[m - l] -= 1
    wall[m - r - 1] +=1 
end
m.times do |i|
    wall[i+1] += wall[i]
end
puts wall.all? {|v| v < 3 } ? "YES" : "NO"