
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 distance between cities A and B is an integer number of kilometers. Along the road between the cities, there are markers every kilometer: on one side, the distance to city A is written, and on the other side, the distance to city B is written. Slava was walking from city A to city B. During his journey, Slava calculated the GCD (Greatest Common Divisor) for the numbers written on each marker. It turned out that only the numbers 1, 3, and 13 appeared as GCDs. What is the distance between the cities?

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