Given a character matrix, your task is to identify the positions of all squares with a length of at least 3 and output the row and column numbers of the bottom-right corner of these squares. The squares are composed of the same character, and each side has a length of at least 3.

If the matrix is

Q L H E X Q Y D Y B E F
L I A M B G X C N J V W
C Q W N F A B U O P B X
F O K I L A Z F L L L G
I V S Q N T M C L L L E
G T V P K H G L L L L I

Please provide the row and column of the bottom-right vertex of the square in the character matrix with a side length of at least 3 (the answer is unique). Notice: All coordinates start from 0.  

Your answer should be in the format <<<[row, column]>>>.