
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
Given $f(x)=\frac{1-x}{1+x}$, the sequence $\{a_n\}$ satisfies $a_1=\frac{1}{2}$, and for any $n\in \mathbb{N}^*$, it holds that $a_{n+2}=f(a_n)$, and $a_n > 0$. If $a_{20}=a_{18}$, then the value of $a_{2016}+a_{2017}$ is ______.

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