output_description: Print the probability that a is odd. Your output will be considered correct
  when its absolute or relative error from the judge's output is at most
  10^{-6}.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
attempt: import sys
  
  sys.setrecursionlimit(10**6)
  int1 = lambda x: int(x) - 1
  p2D = lambda x: print(*x, sep="\n")
  
  
  def IS():
      return sys.stdin.readline()[:-1]
  
  
  def II():
      return int(sys.stdin.readline())
  
  
  def MI():
      return map(int, sys.stdin.readline().split())
  
  
  def LI():
      return list(map(int, sys.stdin.readline().split()))
  
  
  def LI1():
      return list(map(int1, sys.stdin.readline().split()))
  
  
  def LII(rows_number):
      return [II() for _ in range(rows_number)]
  
  
  def LLI(rows_number):
      return [LI() for _ in range(rows_number)]
  
  
  def LLI1(rows_number):
      return [LI1() for _ in range(rows_number)]
  
  
  def main():
      N = II()
      if N % 2 == 0:
          print((N // 2) / N)
      else:
          print(((N // 2) + 1) / N)
  
  
  main()
  
problem_description: Statement
  
  Given is an integer N.
  
  Takahashi chooses an integer a from the positive integers not greater than N
  with equal probability.
  
  Find the probability that a is odd.
samples: [{"input": "4", "output": "0.5000000000\n    \n\nThere are four positive integers not greater than 4: 1, 2, 3, and 4. Among\nthem, we have two odd numbers: 1 and 3. Thus, the answer is \\frac{2}{4} = 0.5.\n\n* * *"}, {"input": "5", "output": "0.6000000000\n    \n\n* * *"}, {"input": "1", "output": "1.0000000000"}]