
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 pond begins with a small patch of algae that triples in size each day. By day 20 of the month, the pond is completely covered with algae. Determine on what day of that month was $75\%$ of the pond still free from algae.

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