
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
Suppose the sequence $\{a\_n\}$ is an arithmetic sequence, with the first term $a\_1 < 0$, $a\_2015 + a\_2016 > 0$, and $a\_2015 \cdot a\_2016 < 0$. Determine the maximum natural number $n$ such that the sum of the first $n$ terms, $S\_n$, is less than 0.

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