@Aastaroth
thanks for your reply!
I'm happy because I can have your opinion!
In that case I'll do it this way?
I define 3 areas in the list of 15000 lines.
Illusion area, free area, reserved area.
1. Illusion area (1-2,000)
This is the same idea as you.
2. Free area (2,001-7,000)
This is...