#!/usr/bin/python

letters = ['a', 'b', 'c', 'd', 'e', 'f']

def testAllCombinationsStartingWith(base, depth):
    for letter in letters:
        newBase = base + letter
        isCorrect = crypt(newBase)
        if (not isCorrect and depth > 1):
            testAllCombinationsStartingWith(newBase, depth - 1)


def crypt(word):
    print 'testing', word
    return False;  # return crypt result here


def main():
    maxLength = 3
    testAllCombinationsStartingWith('', maxLength)

if __name__ == "__main__":
    main()