text: with open("promote.in") as input_file:
      input_lst = [[*map(int, line.split())] for line in input_file]
  
  promotions = [
      promotion[1] - promotion[0] for promotion in input_lst
  ]
  output = []
  for promotion in promotions[::-1]:
      output.append(sum([]))
  
  with open("promote.out", "w") as output_file:
      for promotion in promotions:
          print(promotion, file=output_file)
  
  # print(input_lst)
  