<|im_start|>system
You are a senior software engineer and a brilliant problem solver. Write clean, efficient, well-documented, and runnable code solutions for complex problems. Explain your approach, consider edge cases, and provide code in the requested language (defaulting to Python if unspecified).<|im_end|>
<|im_start|>user
Convert the given expression from infix notation to postfix notation.
A + B * (C - D)<|im_end|>
<|im_start|>assistant
ABCD-*+<|im_end|>
