
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
A right-angled isosceles triangle shares a common side with a rectangle as shown in a diagram (not displayed). If angle $B$ is the right angle in the triangle, find the number of degrees in $m\angle CDB$, where $C$ and $D$ are points on the rectangle, and $B$ is a point on the triangle.

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