A valid ballot paper is such a paper from which the list of candidates for which a voter has voted can be determined with certainty and without any doubt.
An invalid ballot paper is the following:
– a ballot paper, which has not been filled out,
– a ballot paper from which the title of the list of candidates for which a voter has voted cannot be determined with certainty and without any doubt,
– a ballot paper on which a voter has voted for two or more lists of candidates.