
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
Consider a positive integer $n$. Let $\langle n \rangle$ denote the sum of all the positive divisors of $n$ except $n$ itself. For example, $\langle 9 \rangle = 1 + 3 = 4$ and $\langle 18 \rangle = 1 + 2 + 3 + 6 + 9 = 21$. Calculate $\langle \langle \langle 12 \rangle \rangle \rangle$.
A) 6  
B) 9  
C) 12  
D) 15  
E) 21

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