output_description: For each dataset, print the sum of digits in x.
input_description: The input consists of multiple datasets. For each dataset, an integer x is
  given in a line. The number of digits in x does not exceed 1000.
  
  The input ends with a line including single zero. Your program should not
  process for this terminal symbol.
attempt: a = []
  w = 1
  while w != 0:
      w = int(input())
      a.append(w)
  a.pop()
  for i in a:
      s = 0
      for j in range(len(str(i))):
          s += int(str(i)[j])
      print("{0}".format(s))
  
problem_description: Sum of Numbers
  
    
  
  Write a program which reads an integer and prints sum of its digits.
samples: [{"input": "55\n    1000\n    0", "output": "10\n    1"}]