
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
An arithmetic sequence $\{a_n\}$ satisfies: $a_1 = -8$, $a_2 = -6$. If the same number is added to $a_1$, $a_4$, and $a_5$, and the resulting three numbers form a geometric sequence in order, then the added number is $\boxed{-1}$.

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