Contest: Task: Related: TaskA TaskC

Score : $200$ points

We will call a string that can be obtained by concatenating two equal strings an *even* string.
For example, `xyzxyz`

and `aaaaaa`

are even, while `ababab`

and `xyzxy`

are not.

You are given an even string $S$ consisting of lowercase English letters. Find the length of the longest even string that can be obtained by deleting one or more characters from the end of $S$. It is guaranteed that such a non-empty string exists for a given input.

- $2 \leq |S| \leq 200$
- $S$ is an even string consisting of lowercase English letters.
- There exists a non-empty even string that can be obtained by deleting one or more characters from the end of $S$.

Input is given from Standard Input in the following format:

$S$

Print the length of the longest even string that can be obtained.

abaababaab

6

`abaababaab`

itself is even, but we need to delete at least one character.`abaababaa`

is not even.`abaababa`

is not even.`abaabab`

is not even.`abaaba`

is even. Thus, we should print its length, $6$.

xxxx

2

`xxx`

is not even.`xx`

is even.

abcabcabcabc

6

The longest even string that can be obtained is `abcabc`

, whose length is $6$.

akasakaakasakasakaakas

14

The longest even string that can be obtained is `akasakaakasaka`

, whose length is $14$.