
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
On the board are written the numbers 2, 3, 4, ..., 29, 30. For one ruble, you may mark any number. If any number is already marked, you can freely mark its divisors and multiples. For what minimal number of rubles can you mark all the numbers on the board?

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