
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 numbers -3, 2, 7, 11, 15, 18 are rearranged under these rules, where the largest isn't last, but is in one of the first four places, the smallest isn't first, but is in one of the middle three places, and the median isn't first or last, determine the average of the first and last numbers.

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