Squared Words [B]

Memory limit: 32 MB

A squared word is a word of the form , i.e., consisting of a sequence of letters repeated twice. Some examples of squared words in English are the words: couscous, murmur (= a low, continuous sound), tartar (= hardened dental plaque) and hotshots. We would like to find out, for a given word, how many letters should be removed from the word for it to become a squared word (however, not necessarily a correct English word).

Input

The first line of the standard input contains an integer (), denoting the length of the word. The second line contains a word consisting of lower case English letters.

Output

The first and only line of the standard output should contain a single integer - the minimal number of letters that should be removed from the word for it to become a squared word. We assume that the empty word is a correct squared word.

Example

For the input data:

15
tachystoskopach

the correct result is:

7

Explanation of the example: If we remove the letters y, s, o, s, k, o and p, we obtain a squared word tachtach. In Polish, this word represents a (not really well known) kind of a coach.

Task author: Jakub Lacki.