Few know that the cows have their own dictionary with W (1 <= W <=
600) words, each containing no more 25 of the characters 'a'..'z'.
Their cowmunication system, based on mooing, is not very accurate;
sometimes they hear words that do not make any sense. For instance,
Bessie once received a message that said "browndcodw". As it turns
out, the intended message was "browncow" and the two letter "d"s
were noise from other parts of the barnyard.

The cows want you to help them decipher a received message (also
containing only characters in the range 'a'..'z') of length L (2
<= L <= 300) characters that is a bit garbled. In particular, they
know that the message has some extra letters, and they want you to
determine the smallest number of letters that must be removed to
make the message a sequence of words from the dictionary.

INPUT FORMAT:

* Line 1: Two space-separated integers, respectively: W and L

* Line 2: L characters (followed by a newline, of course): the
        received message

* Lines 3..W+2: The cows' dictionary, one word per line

SAMPLE INPUT :

6 10
browndcodw
cow
milk
white
black
brown
farmer


OUTPUT FORMAT:

* Line 1: a single integer that is the smallest number of characters
        that need to be removed to make the message a sequence of
        dictionary words.

2