The Bovine Lexicon  (lexicon.X)

FR's cows have a dictionary, you know. It contains W (6 <= W <= 1000)
words, each at most 20 characters long.  Because 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 of length
L (2 <= L <= 1600) 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.


PROBLEM FILE NAME: lexicon.X


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 (the message contains only the characters
        'a'..'z')

* Lines 3..W+2: The dictionary, one word per line; words consist only
        of the characters 'a'..'z'.


SAMPLE INPUT:

6 10
browndcodw
cow
milk
white
black
brown
farmer


OUTPUT FORMAT:

A single line with a single integer that is the smallest number of
characters that need to be removed to make the message a sequence of
dictionary words.


SAMPLE OUTPUT (file lexicon.out):

2