
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
In a certain country, the airline system is arranged so that each city is connected by airlines with no more than three other cities, and from each city, you can reach any other city with at most one transfer. What is the maximum number of cities that can be in this country?

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