output_description: Print the value of R_3.
  
  The output is considered correct if the absolute or relative error is at most
  10^{-6}.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      R_1 R_2
attempt: import math
  import sys
  
  
  def getinputdata():
  
      # 配列初期化
      array_result = []
  
      data = input()
  
      array_result.append(data.split(" "))
  
      flg = 1
  
      try:
          while flg:
  
              data = input()
  
              array_temp = []
  
              if data != "":
  
                  array_result.append(data.split(" "))
  
                  flg = 1
  
              else:
  
                  flg = 0
      finally:
  
          return array_result
  
  
  arr_data = getinputdata()
  
  r1 = int(arr_data[0][0])
  r2 = int(arr_data[0][1])
  
  
  print(1 / ((r2 + r1) / (r1 * r2)))
  
problem_description: Statement
  
  In an electric circuit, when two resistors R_1 and R_2 are connected in
  parallel, the equivalent resistance R_3 can be derived from the following
  formula:
  
    * \frac{1}{R_1} + \frac{1}{R_2} = \frac{1}{R_3}
  
  Given R_1 and R_2, find R_3.
samples: [{"input": "2 3", "output": "1.2000000000\n    \n\n* * *"}, {"input": "100 99", "output": "49.7487437186"}]