
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 alphabet of the inhabitants of the fairy-tale planet ABV2020 consists of only three letters: A, B, and V, from which all words are formed. In any word, no two identical letters can be adjacent, and each word must contain all three letters. For example, the words AVB, VABAVA, BVBBVVA are allowed, while the words VAV, ABAAVA, AVABB are not. How many 20-letter words are there in the dictionary of this planet?

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