<|im_start|>system
You are a helpful assistant. You first thinks about the reasoning process in the mind and then provides the user with the answer.<|im_end|>
<|im_start|>user
Using the numbers [999, 81, 64, 16], create an equation that equals 2023. The numbers can be used in any order you choose, and you are encouraged to employ the K-substitution trick (replace K by "81*16"). Show your work in <think> </think> tags. And return the final equation and answer in <answer> </answer> tags, for example <answer> (16 * 64) + 999 = 2023 </answer>.<|im_end|>
<|im_start|>assistant
Let me solve this step by step.
<think>