Let A be a 3 × 3 matrix of non-negative real elements such that \(A\left[\begin{array}{l}1 \\ 1 \\ 1\end{array}\right]=3\left[\begin{array}{l}1 \\ 1 \\ 1\end{array}\right]\). Then the maximum value of det(A) is ______.
Enter numerical value using the virtual keypad. Round off where necessary.