Customs clearance steps:
1. First move the [person] out from under the [nest], and then move the [cat] to the [den]
2. After the cat moves to the [nest], it will poop in the [nest].
3. After moving [person] to the edge of [nest], the person will clean up the things [cat] pulls out.
4. After cleaning, four words [soil] will appear.
5. After moving [Soil] to [Whole], a brand new word [Fu] will be formed. At this time, we have completed the level.