
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 a sequence $\{a_n\}$ with the first term $a_1 = -7$, the second term $a_2 = 5$, and satisfying $a_{n+2} = a_n + 2$ (where $n \in \mathbb{N}^+$), find the sum $a_1 + a_3 + a_5 + \ldots + a_{18}$.

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