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

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

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]>>>.