IOIPALIN - Palindrome 2000


A palindrome is a symmetrical string, that is, a string read identically from left to right as well as from right to left. You are to write a program which, given a string, determines the minimal number of characters to be inserted into the string in order to obtain a palindrome. As an example, by inserting 2 characters, the string "Ab3bd" can be transformed into a palindrome ("dAb3bAd" or "Adb3bdA"). However, inserting fewer than 2 characters does not produce a palindrome.

Input

The first line contains one integer: the length of the input string N, 3≤N≤5000. The second line contains one string with length N. The string is formed from uppercase letters from ‘A’ to ‘Z’, lowercase letters from ‘a’ to ‘z’ and digits from ‘0’ to ‘9’. Uppercase and lowercase letters are to be considered distinct.

Output

The first line contains one integer, which is the desired minimal number.

Example

Input:
5
Ab3bd

Output:
2

hide comments
Mauro Persano: 2015-07-28 17:00:58

No spoilers, please!

no name: 2015-07-03 19:16:21

just removed function call overhead, without doing any space or any optimization at all. AC :O
there is just some problem with the time limit, otherwise a simple problem

Last edit: 2015-07-03 19:17:42
Carlos VinĂ­cios: 2015-06-14 10:01:26

I got AC without any space optimization.

Ankit: 2015-06-09 19:04:57

nice que ,AC in one go:)

Last edit: 2015-06-09 19:05:37
:.Mohib.:: 2015-06-06 08:17:24

Awsm que!! Learned a lot...

Last edit: 2015-06-06 08:35:36
Aadil Ahmad: 2015-04-14 14:41:46

Also use scanf/printf instead of cin,cout .

Joker: 2015-03-18 19:51:28

Its Space optimization which causes less reads from virtual memory and gets the solution accepted :)

Abhilash: 2015-01-09 07:59:04

AC with linear space :)

Last edit: 2015-01-09 08:00:09
Divyank Duvedi: 2014-10-19 08:18:18

no space optimisation is required :)

AKASH GOEL: 2014-08-25 21:55:44

space optimization is the key to AC!


Added by:Gareev
Date:2010-08-16
Time limit:0.158s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: NODEJS OBJC PERL6 VB.NET
Resource:IOI 2000, Day 1