Adam rolled two standard six-sided dice once.  What is the probability that he did not roll a prime number on either die? Express your answer as a common fraction.
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Adam rolled two standard six-sided dice once.  What is the probability that he did not roll a prime number on either die? Express your answer as a common fraction.
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
\frac{1}{4}
Adam rolled two standard six-sided dice once.  What is the probability that he did not roll a prime number on either die? Express your answer as a common fraction.
train