
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 line $l: kx - y + 1 = 0$ ($k \in \mathbb{R}$). If there exists a real number $k$ such that line $l$ intersects curve $C$ at points $A$ and $B$, and $|AB| = |k|$, then curve $C$ is said to have property $P$. Given the following three curve equations:  
1. $y = -|x|$;  
2. $x^2 + y^2 - 2y = 0$;  
3. $y = (x + 1)^2$.  
Among them, the serial numbers of the curves that have property $P$ are.

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