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

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

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]>>>.