
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
What is the distance from Beijing to Lanzhou if the distance from Beijing through Lanzhou to Lhasa is 3985 km, and the distance from Lanzhou to Lhasa is 2054 km?

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