Problem Description

Takahashi has become interested in the Takahashi Man function. He wants to calculate $ T(334) $ (where $ T $ represents the Takahashi Man function), but he found out that it would take $ P $ years with modern computers, which is very difficult.

Halfway ready to give up on the calculation, Takahashi learned about Moore's Law. According to Moore's Law, the speed of computers doubles every $ 1.5 $ years, increasing exponentially.

More precisely, after $ x $ years, the speed of computers will be $ 2^{x/1.5} $ times the current speed.

Takahashi wants to start the calculation at the right time to finish the calculation of $ T(334) $ as soon as possible. Of course, he cannot change the computer during the calculation, so the total time to finish the calculation is represented by $ (time until starting the calculation) + (time to calculate $ T(334) $ with the computer at the starting time) $.

Find the shortest time until the calculation is finished.

Input Format

The input is given from the standard input in the following format:

$ P $

Output Format

Output the minimum time it takes for the calculation to finish in one line. The answer will be accepted if the absolute or relative error is within $ 10^{-8} $.

Do not forget to add a newline at the end of the output.

Sample Input and Output

Sample Input #1

3.0000

Sample Output #1

2.8708930019

Sample Input #2

0.0400

Sample Output #2

0.0400000000

Sample Input #3

1000000000000000000.0000

Sample Output #3

90.1855078128

Notes/Hints

Constraints

• $0 \leq P \leq 10^{18}$
• $ P $ is a real number given to four decimal places.

见题面 Input 部分

见题面 Output 部分