How many kinds of tickets do I need to prepare for the train from Station A to the station of Line 5?

How many kinds of tickets do you need to prepare for a train from Station A to bilibili via Station A? I am 15, and the answer is 2 1.

The easiest way to look up a 1 2 3 4 5 B

Count six from a.

5 kinds of numbers 1

Count 2 and 4.

Three counts as three.

Four kinds of counting and two kinds

5 numbers 1 species

Total =2 1