
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
Define $\max\{a,b\}$ as the larger number between real numbers $a$ and $b$. Given a sequence $\{a_n\}$ satisfies $a_1=a (a > 0), a_2=1$ and $a_{n+2}= \frac{2\max\{a_{n+1},2\}}{a_n} (n\in\mathbb{N}^*)$. If $a_{2015}=4a$, denote the sum of the first $n$ terms of the sequence $\{a_n\}$ as $S_n$, then the value of $S_{2018}$ is _________.

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