
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
Through vertex $A$ of an isosceles acute-angled triangle $ABC$ and the center of the circumcircle around this triangle, a line is drawn intersecting side $BC$ at point $D$. Find the length of $AD$, given that $AB = BC = b$ and $\angle ABC = \alpha$.

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