
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 ellipse $\dfrac {x^{2}}{a^{2}}+ \dfrac {y^{2}}{b^{2}}=1(a > b > 0)$ passes through the point $(0,-1)$, and its eccentricity $e= \dfrac { \sqrt {2}}{2}$.  
(I) Find the equation of the ellipse;  
(II) Given a point $P(m,0)$, a line $l$ with slope $k(k\neq 0)$ passing through the point $(1,0)$ intersects the ellipse at points $M$ and $N$. If the x-axis bisects $\angle MPN$, find the value of $m$.

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