Problem Description

Desmond the Moonbear is taking his O-levels. For his literature paper, he has to write a composition! However, this composition is graded using a very special marking scheme that Desmond the Moonbear thought up himself.

Each letter has an awesomeness rating, based on its position in the alphabet ('A' = 1, 'B' = 2... etc). The awesomeness of a composition is the sum of the awesomeness of every single letter in the composition. For example, if the composition consists of "I am dumb.", the awesomeness of this composition will be the sum of the awesomeness of I, A, M, D, U, M and B.

However, due to strict exam regulations, only a given list of N different words can be used in the exam. Each word will not be longer than 100 characters long, and cannot be used twice in a composition. The length of the composition must also not exceed L words. Given a list of all the words allowed in the composition, calculate the maximum awesomeness Desmond the Moonbear can achieve.

Input

The first line of input will contain two integers, N and L.
The next N lines will contain one string each, containing one of the words that is allowed in the composition.

Output

Your output should contain one integer, the maximum awesomeness Desmond the Moonbear can achieve in this composition.

Limits

1 <= L <= N <= 10 000

Sample Input 1

3 2
abba
baa
car

Sample Output 1

28

Sample Input 2

2 1
AaAa
BbBb

Sample Output 2

8