BROKEN - Broken Keyboard


Bruce Force's keyboard is broken, only a few keys are still working. Bruce has figured out he can still type texts by switching the keyboard layout whenever he needs to type a letter which is currently not mapped to any of the m working keys of the keyboard.

You are given a text that Bruce wishes to type, and he asks you if you can tell him the maximum number of consecutive characters in the text which can be typed without having to switch the keyboard layout. For simplicity, we assume that each key of the keyboard will be mapped to exactly one character, and it is not possible to type other characters by combination of different keys. This means that Bruce wants to know the length of the largest substring of the text which consists of at most m different characters.

Input

The input contains several test cases, each test case consisting of two lines. The first line of each test case contains the number m (1 ≤ m ≤ 128), which specifies how many keys on the keyboard are still working. The second line of each test case contains the text which Bruce wants to type. You may assume that the length of this text does not exceed 1 million characters. Note that the input may contain space characters, which should be handled like any other character.

The last test case is followed by a line containing one zero.

Output

For each test case, print one line with the length of the largest substring of the text which consists of at most m different characters.

Example

Input:
5
This can't be solved by brute force.
1
Mississippi
0

Output:
7
2

hide comments
time1416: 2018-08-21 10:10:50

make sure to clear the frequency array after each case if you are doing two pointers :3

hello_world123: 2018-06-23 09:35:16

Problem Setter please give me the test at which my code is failing.
Thanks

anirudnits: 2018-02-14 07:08:22

O(n), TLE in python 3.5 but accepted in PYPY

utkarsh22garg: 2017-11-11 08:24:03

Good question..
Try the test cases..
5
mnin
1
s
0

output-
4
1

Shubham Jadhav: 2017-06-23 13:57:18

AC in one go :)

papan_97: 2017-05-19 15:53:34

ACed in second go with 0.02s with O(n) solution :)

hrishabh: 2017-05-11 12:12:49

n^2 will work or not in python?

suraj_: 2016-11-01 04:52:20

AC !! in one go. my 50th

harshgupta007: 2016-10-04 08:31:14

Nice problem. Look for testcases like
1
aaaaabbaaa

sumitsinghnit: 2016-08-04 08:35:30

I don't know why but c gave tle, c++5.1 gave runtime error, but finally accepted in c++14 using same code after lot of failed attempts.

Last edit: 2016-08-04 08:36:13

Added by:Adrian Kuegel
Date:2008-07-12
Time limit:4.358s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ERL JS-RHINO NODEJS PERL6 VB.NET
Resource:University of Ulm Local Contest 2008