
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
Sarah is designing a tiled surface for a park, arranged as a large square containing nine smaller, identically sized circles. Each circle is tangent to the square's sides and to adjacent circles. If the square's side length is designed to be 27 feet, calculate the total unoccupied (shaded) area on the surface.

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