In this task, you are given a premise sentence. Your task is to write a new sentence by substituting the subject and object (i.e., the input's subject should be output's object and vice versa.). The generated sentence must be fluent and shouldn't change the voice (i.e., passive or active) of the input.

Example Input: The author helped the professor .
Example Output: The professor helped the author .

Example Input: The doctor recognized the artists who the managers called .
Example Output: The artists recognized the doctor .

Example Input: The doctors who the presidents believed mentioned the athlete .
Example Output:
The presidents mentioned the doctors .