def get_nr_to_check(selection, line_scores):
    """
    Gets the number of checks the annotators should do given a selection and a line_score
    :param selection: selection of the lines to check
    :param line_scores: the lines with the given score
    :return: the number of checks that still need to be performed
    """
    total_checks = 0
    maximum_checks = 0
    for (name, lines), (name2, (lines_with_score)) in zip(selection, line_scores):
        score = sum([score for (line, score) in lines_with_score if line in lines])
        max_score = len(lines) * 2
        total_checks += score
        maximum_checks += max_score
    return maximum_checks - total_checks