Score : $200$ points

Problem Statement

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.

Constraints

• $2 \leq |S| \leq 200$
• $S$ 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

Input is given from Standard Input in the following format:

$S$

Output

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 $14$.