
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
A railway network of four straight segments is to be built among five cities in such a way that it is possible to travel from any city to any other city. (None of the three cities are collinear. The segments can also intersect each other.) How many such railway networks are possible?

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