
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
Line  $l$  tangents unit circle  $S$  in point  $P$ . Point  $A$  and circle  $S$  are on the same side of  $l$ , and the distance from  $A$  to  $l$  is  $h$  ( $h > 2$ ). Two tangents of circle  $S$  are drawn from  $A$ , and intersect line  $l$  at points  $B$  and  $C$  respectively. 

Find the value of  $PB \cdot PC$ .

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