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

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

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]>>>.