I apologise if this question has already been addressed.
Say I have a set up like this:
I have a main folder in which I have both preamble.tex and a folder sub_1. In sub_1, there is another folder sub_2 - and in sub_2 there is my_file.tex
What must I write in my_file.tex in order to input preamble.tex? A cursory google and tex.stackexchange search of "input" and "different directory" seems only to address the case when, say, the preamble is located in some subdirectory of where the main file is.
Any help is appreciated.