
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
Let $l_1$ be the tangent line to the curve $f(x) = e^x + x$ (where $e$ is the base of the natural logarithm), and let the equation of the line $l_2$ be $2x - y + 3 = 0$. Given that $l_1$ is parallel to $l_2$, find the distance between the lines $l_1$ and $l_2$.

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