
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 $-5, 2, 7, 10$ and $15$ are rearranged according to these rules: 

        1. The largest isn't second but must be among the first four places.
        2. The smallest isn't third but must be among the last four places.
        3. The median isn't last or first.

Determine the average of the first and last numbers.

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