
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
At the stadium, an equal number of fans entered through checkpoints numbered 1, 2, and 3. They then passed through several more checkpoints, moving according to arrows and dividing equally at forks. At checkpoint 7, 15 people were checked. How many people passed through checkpoint 8?

Checkpoints (KPP - control points) are where stadium staff check spectators for tickets and prohibited items.

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