
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
For the line $l_1: ax - y - a + 2 = 0$ (where $a \in \mathbb{R}$), the line $l_2$ passing through the origin $O$ is perpendicular to $l_1$, and the foot of the perpendicular from $O$ is $M$. Then, the maximum value of $|OM|$ is ______.

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