
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
To each positive integer  $ n$  it is assigned a non-negative integer  $f(n)$  such that the following conditions are satisfied:

(1)  $ f(rs) \equal{} f(r)\plus{}f(s)$ (2)  $ f(n) \equal{} 0$ , if the first digit (from right to left) of  $ n$  is 3.
(3)  $ f(10) \equal{} 0$ .

Find  $f(1985)$ . Justify your answer.

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