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

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

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]>>>.