| Problem Author: | Oleksandr Tymkovich |
| Prepared by: | Oleksandr Tymkovich, Feysa Bohdan |
| Editorial by: | Oleksandr Tymkovich |
For example, if you want a box to contain only yellow balls, then you need to rearrange all the blue balls from it. If the task is to make the box empty, then you need to rearrange all the balls from it.