
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
To process a certain workpiece, it takes 20 days for A to complete it alone, and only 10 days for B to complete the task. Now it is required that both persons complete the task within 12 days. How many days must B work before A continues the processing to exactly meet the deadline?

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