
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
Numbers from 1 through 81 are written sequentially on a 9 by 9 grid checkerboard, where each successive row continues the sequence from the previous row. Calculate the sum of the numbers in the four corners of this 9x9 checkerboard.

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