def stemmer(word):
    """Return leading consonants (if any), and 'stem' of word"""

    word = word.lower()
    pos = list(
        filter(lambda v: v >= 0,
               map(lambda c: word.index(c) if c in word else -1, 'aeiou')))
    if pos:
        first = min(pos)
        return (word[:first], word[first:])
    else:
        return (word, '')