An abelian square is a string of even length where the first half of the string is an anagram of the second half of the string. Here are some examples:

• hannah is an abelian square.
• reappear is an abelian square.
• racecar is NOT an abelian square as it has odd length.
• soot is NOT an abelian square, but the substring oo is an abelian square.

Given a string, determine the length of the longest substring that is an abelian square.

Input Specification

The first line of input contains an integer ~N~ ~(1 \le N \le 10~ ~000)~. The next line contains a lower-case string of ~N~ characters.

Output Specification

The length of the longest substring that is an abelian square.

Sample Input 1

8
reappear

Sample Output 1

8

Sample Input 2

11
programming

Sample Output 2

2