
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
According to relevant regulations, driving a motor vehicle with a blood alcohol concentration (BAC) of 20 mg/100 ml or higher constitutes drunk driving. Suppose after drinking, an individual's blood alcohol concentration is $p_0$ mg/100 ml. After $x$ hours, the concentration drops to $p$ mg/100 ml, which satisfies the relation $p = p_0 \cdot e^{rx}$ ($r$ is a constant). If someone has a BAC of 89 mg/100 ml after drinking and it decreases to 61 mg/100 ml 2 hours later, this person must wait for ____ hours before driving. Give the answer accurate to the nearest hour.

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