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

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

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]>>>.