output_description: For each dataset, print x and y in ascending order in a line. Put a single
  space between x and y.
input_description: The input consists of multiple datasets. Each dataset consists of two integers
  x and y separated by a single space.
  
  The input ends with two 0 (when both x and y are zero). Your program should
  not process for these terminal symbols.
attempt: a = 100
  while a != 0:
      lis = [int(x) for x in input().split()]
      if lis[0] * lis[1] != 0:
          lis.sort()
          print(lis[0], end=" ")
          print(lis[1])
      a = lis[0] * lis[1]
  
problem_description: Swapping Two Numbers
  
  Write a program which reads two integers x and y, and prints them in ascending
  order.
samples: [{"input": "2\n    2 2\n    5 3\n    0 0", "output": "3\n    2 2\n    3 5"}]