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

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

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]>>>.