
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
A number  $p$  is  $perfect$  if the sum of its divisors, except  $p$  is  $p$ . Let  $f$  be a function such that:

 $f(n)=0$ , if n is perfect
 $f(n)=0$ , if the last digit of n is 4
 $f(a.b)=f(a)+f(b)$ 

Find  $f(1998)$ 

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