
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 the sequence {a<sub>n</sub>} where a<sub>n</sub> is defined as $$\begin{cases} \frac {1}{n^{2}+2n}，n\text{ is odd} \\ sin \frac {nπ}{4}，n\text{ is even}\end{cases}$$, and S<sub>n</sub> is the sum of the first n terms of the sequence {a<sub>n</sub>}, find S<sub>2018</sub>.

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