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

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

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]>>>.