How many digits are there in the base-7 representation of $956$?
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
How many digits are there in the base-7 representation of $956$?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
4
How many digits are there in the base-7 representation of $956$?
train