Teacher is teaching 2 lessons per week in class 5A but both are in the afternoon.

You instruct the generator to balance the lessons so that if teacher is teaching only two or three lessons in one class they shall not be placed every time late in the day.

You have two options:
1. Max one history lesson on 6th-7th position in each class (solution 1)
or
2. Specify how many lessons shall be before certain position