
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
The road connecting two villages on a mountain consists only of uphill or downhill segments. A bus always travels at $15 \mathrm{~km/h}$ on uphill segments and at $30 \mathrm{~km/h}$ on downhill segments. Find the distance between the villages if the bus takes exactly 4 hours to complete the round trip.

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