-1
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Find $\sin \left( -\frac{\pi}{2} \right).$
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
-1
Find $\sin \left( -\frac{\pi}{2} \right).$
train