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

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