
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 certain product has 4 defective items and 6 non-defective items, each item being distinct and identifiable. Now, if one item is tested at a time until all 4 defective items are identified, the number of different scenarios in which the last defective item is discovered exactly on the fifth test is ______.

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