Problem Description

When people input text, besides typing character by character, they can also use the clipboard to copy. Typing one letter takes $1$ unit of time. Copying the part that has already been typed into the clipboard takes $5$ units of time (Ctrl+A, Ctrl+C, then cancel the select-all state). Pasting the clipboard content takes $2$ units of time (Ctrl+V).

If we do not care about the actual content of the text and only care about its length, what is the minimum time needed to input a text whose length is at least $n$?

Note: The Constraints are slightly different from the original problem.

Input Format

A positive integer $n$, representing the length of the text.

Output Format

A positive integer $t$, representing the minimum time needed.

20

16

Hint

Sample explanation: First spend $7$ units of time to type $7$ characters, then copy (costs $5$ units of time), paste twice (costs $4$ units of time), and you can type $21$ characters in $16$ units of time.

For $20\%$ of the testdata, $n\le 10$.

For $60\%$ of the testdata, $n\le 10^4$.

For $100\%$ of the testdata, $n\le 4\times 10^4$.

Translated by ChatGPT 5