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
:.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!

mohsin mohammad: 2014-08-11 19:09:21

happy DP :) AC!

Sachin Malhotra: 2014-07-27 23:53:05

ummm.. In Love with DP :) :)..

Sachin Malhotra: 2014-07-27 22:30:22

Bottom up also giving TLE :(

Last edit: 2014-07-27 22:58:12
Mohamed Essam: 2014-06-09 11:44:58

Changed variable names, got AC -_-


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