output_description: For each dataset, print the standard deviation in a line. The output should
  not contain an absolute error greater than 10-4.
input_description: The input consists of multiple datasets. Each dataset is given in the
  following format:
  
      
      
      n
      s1 s2 ... sn
      
  
  The input ends with single zero for n.
attempt: import sys
  import math
  import decimal
  
  args = []
  for l in sys.stdin:
      args.append(l)
  lines = []
  cnt = 0
  
  while cnt < int(len(args)) - 1:
      num = int(args[cnt])
      cnt += 1
      if num == 0:
          continue
      data = args[cnt].split(" ")
      cnt += 1
  
      numLine = []
      for points in data:
          numLine.append(int(points))
  
      average = 0.0
      for points in numLine:
          average += int(points)
      average /= num
  
      distributed = []
      for points in numLine:
          distributed.append((points - average) * (points - average))
  
      std_dev = 0.0
      for value in distributed:
          std_dev += value
  
      lines.append(math.sqrt(std_dev / num))
  
  for line in lines:
      result = decimal.Decimal(line).quantize(decimal.Decimal("0.00000000"))
      if decimal.Decimal(0e-8) == result:
          print("0.00000000")
      else:
          print(result)
  
problem_description: Standard Deviation
  
    
  
  You have final scores of an examination for n students. Calculate standard
  deviation of the scores s1, s2 ... sn.
  
  The variance α2 is defined by
  
  α2 = (∑n _i_ =1(s _i_ \- m)2)/n
  
  where m is an average of si. The standard deviation of the scores is the
  square root of their variance.
samples: [{"input": "70 80 100 90 20\n    3\n    80 80 80\n    0", "output": ".85677655\n    0.00000000"}]