When he is not making videos for his YouTube channel, the famous programmer
influencer Krokod likes to play boardgames with his friend Paula. He wants to
play the game *7Krokods*, but Paula doesn't like complex games, so Krokod decided
that they will play only with green and crocodile cards.

Paula has green cards, and each of them has one of the following letters written on
it: `d`

, `k`

, `o`

, or `r`

. Her total score is defined as the sum of the following components:

- For each letter, she gets as many points as is the number of cards with that
letter written on them, squared. For example, if she has cards with the letter
`k`

, she gets points. - For each word
`krokod`

she can make from her cards, she gets an extra points.

*Illustration of the first example.*

*Paula has letters*

`d`

, letters `k`

, letters `o`

and
letters `r`

. The word `krokod`

can be spelled times . Her total score is . Paula also has crocodile cards. She can replace each of the crocodile cards with a green card having a letter of her choice. She will do it in a way that maximizes her score.

Help her determine the maximum score she can get with her cards.

#### Input Specification

The first line contains integers and , the number of green cards and the number of crocodile cards.

The second line contains a sequence of characters, where the character represents the letter on the
green card. The sequence consists only of characters `d`

, `k`

, `o`

and `r`

.

#### Output Specification

In the first and only line, output Paula's maximum possible score.

#### Constraints

Subtask | Points | Constraints |
---|---|---|

1 | 17 | |

2 | 26 | |

3 | 7 | No additional constraints. |

#### Sample Input 1

```
15 0
krokodkrokodkrk
```

#### Sample Output 1

`79`

#### Explanation for Sample 1

Look at the illustration in the task statement.

#### Sample Input 2

```
5 1
rokod
```

#### Sample Output 2

`17`

#### Explanation for Sample 2

For the maximum possible score, Paula can replace her crocodile card with a green card having the letter `k`

.

#### Sample Input 3

```
8 2
ddkkoorr
```

#### Sample Output 3

`35`

## Comments