def relative_len_difference(lca, lcb):
    """
    :param lca: lcase words in sent_a, without stopwords
    :param lcb: lcase words in sent_b, without stopwords
    :return: Float, a similarity score

    Get ratio of sentence difference to the maximum sentence length
    """
    la, lb = len(lca), len(lcb)
    return abs(la - lb) / float(max(la, lb) + 1e-5)