2024 Gauss 8 Problem 10

In the diagram, a square with side length 6 is partially shaded. The largest shaded region is a square with side length 3. The other two shaded regions are squares with side lengths 2 and 1. What is the total area of the unshaded region?

\textbf{(A)}\ 12\quad \textbf{(B)}\ 18\quad \textbf{(C)}\ 22\quad \textbf{(D)}\ 24\quad \textbf{(E)}\ 30

If there are no answer choices shown, enter a numerical answer.

Full credit to this problem is given to the CEMC, you may view all Gauss contests here.