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

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

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]>>>.