
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 unit purchased a vacant lot for 21.6 million yuan and plans to build a building of at least 10 floors, with each floor being 2000 square meters. It is calculated that if the building is built to x (x≥10) floors, the average construction cost per square meter will be 560+48x (unit: yuan). To minimize the average comprehensive cost per square meter of the building, how many floors should the building have?  
(Note: Average comprehensive cost = Average construction cost + Average land purchase cost, Average land purchase cost = $$\frac {\text{Total land purchase cost}}{\text{Total construction area}}$$)

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