
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 $-3, 5, 7, 10, 15$ are rearranged according to the following rules: 
1. The largest number is not in the last place, but it is within the last three places.
2. The smallest number is not in the first place, but it is within the first three places.
3. The median number is neither in the first nor in the last place. Determine the sum of the second and fourth numbers.

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