
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
Given the sequence ${a_n}$ that satisfies: $a_1=1$, $a_{n+1}-a_n \in {a_1, a_2, ..., a_n}$ $(n \in \mathbb{N}^+)$, let $a$ be the maximum value of $a_{10}$ among all sequences that meet the condition, and $b$ be the minimum value. Find $a-b=$ _______.

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