Dean ordered 2 large pizzas that were each cut into 12 slices.  His friends Frank and Sammy came over to enjoy some pizza and watch a movie.  Dean was hungry and ate half of the Hawaiian pizza.  Frank only ate 3 slices of Hawaiian pizza and Sammy ate a third of the cheese pizza.  How many total slices were left over?
Please reason step by step, and put your final answer within \boxed{}.
user