For the application of articles 296,297 and 298, the defence may not challenge more than one assessor-judge at first instance and more than two on appeal. The public prosecutor may not challenge any of them. The number of assessor-jurors drawn by lot is three in the first instance and six in the appeal instance and the trial jury is formed at the moment when the names of the three or six assessor-jurors respectively who have not been challenged are taken from the ballot box.