
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
A library has eight identical copies of a particular book. At all times, a number of these copies are available at the library while others are checked out. Determine how many different configurations there are for some of the books to be in the library and the remainder to be checked out, assuming that at least one book is in the library and at least one is checked out. (The books should be considered indistinguishable.)

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