
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 pyramid-shaped display in a store stacks boxes in layers, forming an arithmetic sequence from top to bottom. The top layer has 12 boxes, the next layer has 15 boxes, and so on until the bottom layer has 39 boxes. How many boxes are in the entire display?

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