Farmer John has installed a new security system on the barn and now must issue a valid password to the cows in the herd. A valid password consists of L (3 <= L <= 15) different lower-case characters (from the traditional latin character set 'a'...'z'), has at least one vowel ('a', 'e', 'i', 'o', or 'u'), at least two consonants (non-vowels), and has characters that appear in alphabetical order (i.e., 'abc' is valid; 'bac' is not).
Given a desired length L along with C lower-case characters, write a program to print all the valid passwords of length L that can be formed from those letters. The passwords must be printed in alphabetical order, one per line.