<|im_start|>system
You are a helpful assistant. You first think about the reasoning process in the mind and then provide the user with the answer. You should try to truely solve the question by yourself without cheating.  <|im_end|>
<|im_start|>user
 A safe has five locks, and the keys are cloned and distributed among eight people such that any five of the eight people can open the safe. What is the least total number of keys required to satisfy this condition? Show your work in <think> </think> tags. And return the final answer in <answer> </answer> tags.<|im_end|>
<|im_start|>assistant
Let me solve this step by step.
<think>
user
20
A safe has five locks, and the keys are cloned and distributed among eight people such that any five of the eight people can open the safe. What is the least total number of keys required to satisfy this condition?
test