text: """
  In this challenge, we practice calculating standard deviation.
  """
  
  from math import sqrt
  
  def mean(X):
      """
      Return the mean of X
      """
      if not X:
          return None
  
      sum = 0
      for x in X:
          sum += x 
      return sum/len(X)
  
  def std(X):
      """
      Return the std of X
      """
      if not X:
          return None
  
      mean_X = mean(X)
  
      sum_squared_error = 0
      for x in X:
          sum_squared_error += (x - mean_X)**2
  
      return sqrt(sum_squared_error/len(X))
  
  # read the first line to get N
  N = int(input())
  
  # read the second line to get X
  X = [int(s) for s in input().split()]
  
  print(round(std(X), 1))