
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
How many different four-digit numbers, divisible by 4, can be composed of the digits 1, 2, 3, and 4,

a) if each digit can occur only once?

b) if each digit can occur multiple times?

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