<|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
 Jirka had three identical rectangles. First, he placed them next to each other as shown in the picture and obtained a rectangle with a perimeter of $20 \mathrm{~cm}$. He then arranged them differently and obtained a rectangle with a different perimeter. What was the perimeter of this rectangle? (In each arrangement, no two rectangles overlap and there are no gaps between them.) 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
28
Jirka had three identical rectangles. First, he placed them next to each other as shown in the picture and obtained a rectangle with a perimeter of $20 \mathrm{~cm}$. He then arranged them differently and obtained a rectangle with a different perimeter. What was the perimeter of this rectangle? (In each arrangement, no two rectangles overlap and there are no gaps between them.)
test