n, k = gets.split.map(&:to_i)

if k>=n
  puts 'NO'
else
  # 4 => 3
  # 5 => 4
  # 6 =>
  if n % 2 == 0
    if k > (n / 2)
      puts 'NO'
    else
      puts 'YES'
    end
  else
    if k > (n / 2) + 1
      puts 'NO'
    else
      puts 'YES'
    end
  end
end
