
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 that the line $l: y=x+1$ intersects the $x$-axis and $y$-axis at points $M$ and $N$ respectively, and intersects the circle $C: (x-4)^{2}+y^{2}=16$ at points $A$ and $B$, with the midpoint of chord $AB$ being $P$, find the value of $\overrightarrow{MN}•\overrightarrow{MP}$.

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