
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 company spent 90,000 yuan to purchase a new device for production. The first year's operational cost is 20,000 yuan, and from the second year onwards, the annual operational cost increases by 30,000 yuan each year. The income generated by the device is 210,000 yuan annually. Determine the number of years (n) that the device was used, at which point the total profit reaches its maximum value.

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