Description

JYY has two strings $A$ and $B$, both of length $N$.

A "twisted string" $S(i,j,k)$ is formed by concatenating the substring of $A$ from the $i$-th character to the $j$-th character and the substring of $B$ from the $j$-th character to the $k$-th character.

For example, if $A=\mathtt{XYZ}$ and $B=\mathtt{UVW}$, then the twisted string $S(1,2,3)=\mathtt{XYVW}$.

JYY defines a "twisted palindrome" as one of the following:

• A palindrome in $A$;
• A palindrome in $B$;
• Or a twisted string $S(i,j,k)$ that is a palindrome.

Now JYY wants to find the longest twisted palindrome.

Input Format

The first line contains a positive integer $N$. The second line contains a string $A$ of length $N$ consisting of uppercase letters. The third line contains a string $B$ of length $N$ consisting of uppercase letters.

Output Format

Output a single integer on the first line, the length of the longest twisted palindrome.

5
ABCDE
BAECB

5

Hint

Sample explanation: The twisted palindrome in the best solution is shown below (characters not in the palindrome are marked with .):

.BC..
..ECB

Constraints: For all testdata, $1 \leq N \leq 10^5$.

Translated by ChatGPT 5