Mostly Muffins sells 15 different kinds of muffins. Five of these kinds can be purchased only as small muffins and the other ten kinds can be purchased only as large muffins. The small muffins cost $1 each and the large muffins cost $2 each. Susan decides to order $4 worth of muffins, with each muffin she orders being a different kind. How many different muffin orders can Susan make?