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

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]>>>.