
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
From 80 products numbered $1, 2, \ldots, 80$, a sample of size $5$ is drawn using systematic sampling. If the product numbered $42$ is in the sample, then the first product's number in this sample is ______.

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