There are 56 passengers. Therefore, this bus has at least 56 seats.
At least the number of seats is the maximum number of passengers, and the total number of passengers is:
Starting point: 14
1: 14+ 13- 1=26
2:26+ 12-2=36
3:36+ 1 1-3=44
4:44+ 10-4=50
5:50+9-5=54
6:54+8-6=56
7:56+7-7=56
8:56+6-8=54
…………
So there must be at least 56 seats.