
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
Let the function $f(x) (x \in \mathbb{R})$ satisfy $f(x - \pi) = f(x) + \sin x$. When $0 \leqslant x \leqslant \pi, f(x) = 1$, find $f(- \frac{13 \pi}{6})$.

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