
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 non-empty sets $A$ and $B$ satisfying the following two conditions:  
$(ⅰ) A \cup B = \{1,2,3,4\}$, $A \cap B = \varnothing$;  
$(ⅱ)$ The number of elements in set $A$ is not an element of $A$, and the number of elements in set $B$ is not an element of $B$.  
Then, represent set $A$ using the roster method as ______.

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