Urban traffic is always very congested, especially when commuting to and from get off work, the bus station always gathers a group of people who want to take the bus. You need to arrange for these people to board the bus. You need to allow every bus to take as many people as possible, because the number of bus classes is limited, and you need to allow everyone to get on the bus. But you also have to control the number of people on the bus, because too many passengers will overwhelm the bus. Have fun!