
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
In the arithmetic sequence {a<sub>n</sub>}, a<sub>8</sub> = 29, a<sub>18</sub> = -1,
1. From which term does the sequence start to become negative?
2. How many terms should be added to get the maximum sum?
3. Find the sum of the first n terms of the sequence {|a<sub>n</sub>|}.

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