<|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
 If 10 boys meet at a reunion and each boy shakes hands exactly once with each of the others in a specific order, such that each boy must first shake hands with the boy whose age is one year younger than him and then with the boy whose age is one year older than him (except for the youngest and the oldest boys, who only shake hands with the boy 1 year older and 1 year younger, respectively), what is the total number of handshakes that occurred? 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
43
If 10 boys meet at a reunion and each boy shakes hands exactly once with each of the others in a specific order, such that each boy must first shake hands with the boy whose age is one year younger than him and then with the boy whose age is one year older than him (except for the youngest and the oldest boys, who only shake hands with the boy 1 year older and 1 year younger, respectively), what is the total number of handshakes that occurred?
test