Nutter is a weird kid. As an infant, he was obsessed with the prefixes of `nutt`

(`nut`

, `nu`

, and `n`

), but hated the word `nutt`

itself. When his parents bought him a box of Scrabble, he realized that the board already contained a single word: `putt`

, which got him thinking. He wondered how he could add, swap, or remove blocks from a word to make all the prefixes of another word .

Nutter has access to an infinite supply of Scrabble blocks, and can only add, swap, or remove blocks to form his desired prefixes. Each operation takes 1 move, but since he's quick with his hands, he isn't worrying about shifting blocks (you can add, swap, or remove non-terminal blocks). Nutter wants to know how he can turn word into word 's prefixes (not including word itself) using the minimum number of moves.

#### Constraints

**Subtask 1 [20%]:** .

**Subtask 2 [80%]:** .

#### Input Specification

The first line of input will contain two integers and separated by a single space. The second line will contain a single string of length , and the third line will contain a single string of length .

#### Output Specification

Output a single integer representing the minimum number of moves to change word to all of word 's prefixes.

#### Sample Input

```
4 4
nutt
putt
```

#### Sample Output

`9`

#### Explanation

The prefixes of `putt`

are `put`

, `pu`

, and `p`

, and Nutter wants to try and make them all from the word `nutt`

.

To get `put`

from `nutt`

, swap the `n`

with a `p`

and remove a `t`

from the end (2 operations).

To get `pu`

, do the same operations as `put`

, but remove another `t`

(3 operations + 2 = 5 total).

To get `p`

, do the same operations as `pu`

, but remove the `u`

at the end (4 operations + 5 = 9 total).

Since Nutter doesn't want to make `putt`

itself, he uses 9 operations in total.

## Comments

Words ARE case-sensitive.

Swap = Replace 1 character from word A WITH another character to MAKE word B.

What can be swapped? Is it allowed to...

Also, are the words case-sensitive?

I hope these can be clarified. Thank you.