Given a disfluent sentence, modify the sentence to it to its equivalent fluent form, preserving the meaning of the sentence.

Example input: Who did the Han Chinese want to help the Khitan no I mean the Mongols fight?
Example output: Who did the Han Chinese want to help the Mongols fight?
Example explanation: The input initially means Khitan and then changes to Mongols, hence this is correct.
Q: What compounds er uh what is the process by which the adaptive immune system is evaded by the chainging of non-essential epitopes called?
A:
What is the process by which the adaptive immune system is evaded by the chainging of non-essential epitopes called?