The front view and the plan from above of a stack of cubes are given. What is the largest number of cubes the stack can contain?

Every shaded square of the plan holds a column, and no column can be taller than the front view shows for its line. Left line: 2 squares, up to 3 each: 6. Middle line: 2 squares, up to 1 each: 2. Right line: 3 squares, up to 2 each: 6. Largest $6+2+6=14$. (10 is the smallest.)