
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
Let  $n > 1$  be an integer and  $X = \{1, 2, \cdots , n^2 \}$ . If there exist  $x, y$  such that  $x^2\mid y$  in all subsets of  $X$  with  $k$  elements, find the least possible value of  $k$ .

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