
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
For a positive integer  $n$  not divisible by  $211$ , let  $f(n)$  denote the smallest positive integer  $k$  such that  $n^k - 1$  is divisible by  $211$ . Find the remainder when   $$ \sum_{n=1}^{210} nf(n) $$   is divided by  $211$ .

*Proposed by ApraTrip*

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