
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
An 11-digit mobile phone number starts with 1390931. Given that the remaining 4 digits can only be 1, 3, or 5, and each of these digits must appear at least once, how many such mobile phone numbers are there?

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