
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
Let  $S$  be the set of positive integer divisors of  $20^9.$  Three numbers are chosen independently and at random from the set  $S$  and labeled  $a_1,a_2,$  and  $a_3$  in the order they are chosen. The probability that both  $a_1$  divides  $a_2$  and  $a_2$  divides  $a_3$  is  $\frac mn,$  where  $m$  and  $n$  are relatively prime positive integers. Find  $m.$ 

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