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

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

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]>>>.