
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 A, B, C are the three interior angles of triangle ABC, and vectors $\overrightarrow{m} = (\sin B+\sin C, 0)$, $\overrightarrow{n} = (0, \sin A)$, with the condition that $|\overrightarrow{m}|^2 - |\overrightarrow{n}|^2 = \sin B \sin C$:
1. Determine the size of angle A.
2. Determine the range of values that $\sin B+\sin C$ can take.

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