
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
The railway between Beijing and Lanzhou has 25 stations (including Beijing and Lanzhou). How many types of tickets are needed to meet the ticketing requirements?

Present the answer in LaTex format: \boxed{Your answer}
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