I want Python code for problem regarding martingale situation for a coin toss

  1. At the beginning of the game, you are given N as input.
  2. Set V=N, and set X=1
  3. Flip a fair coin.
    3a. If the coin lands on heads: Increase V by X, and then set X=1
    3b. If the coin lands on tails: Decrease V by X, and then set X=2X
  4. If V less than or equal to 0 or V greater than or equal to 2N
    4a. End the game.
  5. Proceed to step 3.
    Given the initial value N, what is the expected number of turns (coin flips) you will play before ending the game?
    constraints-Input:
    Input consists of a single integer, N (with 1≤N≤1,000,000), the initial input to the game.

Output:
A single decimal number, containing the expected number of turns you will play this game before it ends. Your output will be accepted if it is within 10−6 absolute or relative error.

Sample Input 1:
1
Sample Output 1:
1.000000000000
Sample Input 2:
3
Sample Output 2:
3.9609375

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