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

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

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]>>>.