
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
Find the total number of 7-digit natural numbers whose digits in the decimal representation are in strictly increasing order up to the middle, and then in strictly decreasing order. For example, the number 1358620 meets this criterion.

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