
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 high-rise building decoration requires 50 meters of aluminum material. There are several models available for selection: 3 meters, 6 meters, 9 meters, 12 meters, 15 meters, 19 meters, 21 meters, and 30 meters. If you are the purchaser and want the total length of the aluminum material to be exactly 50 meters, which purchasing plan should you choose?

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