
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
I have fifteen books, of which I want to bring two to read on vacation. However, out of these, there are three specific books that cannot be paired together (let's say they are volumes of the same series). How many different pairs can I choose?

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