menu with all child pages

Hi guys. I need find simply solution how to create menu with all child pages. to be well understood, i know plugins who allow to create auto-menu with child pages, like gecka submenu, but I looking for different solution. I need create menu with perm function. So I can later edit all menu titles. all plugins don’t allow me to do this because generate a menu items automatic.
What I need to do is a create menu with all child pages for permanent but is a hard to add manual over 300 items to 20 separate menus.

any solution how to do this? tnx.