Kirinriki

Problem Description

We define the distance of two strings A and B with same length n is $dis_{A,B} = \sum\limits_{i=0}^{n-1}|A_{i}-B_{n-1-i}|$ The difference between the two characters is defined as the difference in ASCII. You should find the maximum length of two non-overlapping substrings in given string S, and the distance between them are less then or equal to m.

Input

The first line of the input gives the number of test cases T; T test cases follow. Each case begins with one line with one integers m : the limit distance of substring. Then a string S follow. Limits $T \leq 100$ $0 \leq m \leq 5000$ Each character in the string is lowercase letter, $2 \leq |S| \leq 5000$ $\sum |S| \leq 20000$

Output

For each test case output one interge denotes the answer : the maximum length of the substring.

Sample Input

1

5

abcdefedcb

Sample Output

5

Hint

[0, 4] abcde [5, 9] fedcb The distance between them is abs('a' - 'b') + abs('b' - 'c') + abs('c' - 'd') + abs('d' - 'e') + abs('e' - 'f') = 5

Source

2017 Multi-University Training Contest - Team 6

https://acm.hdu.edu.cn/showproblem.php?pid=6103