To reduce greasy splatters and messy spills, Ann wants to install a backsplash behind her stove. She needs to cover a region that stretches 27 inches by 81 inches. She has several mosaic tiles of different sizes. The red tiles measure 9 inches by 9 inches, the blue tiles measure 18 inches by 18 inches and the green tiles measure 27 inches by 27 inches. How many different ways can she tile her space?