Bus Seat Numbering

There is a bus with 30 seats. The seats are numbered from 1 to 30, and the numbering is as depicted in this image. As can be seen in the image, the bus is divided into two decks - The Lower deck, and the Upper deck, with 15 seats each. And some of the seats come as Single and some as Double. For example, Seats 1 and 2 are Double, whereas Seat 11 is a Single. You will be given a Seat number, an