What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_13, x_13 will listen to a song or x_13 is not a janitor. For all x_13, x_13 will listen to a song or x_13 will not read a book. For all x_13, x_13 is a janitor.
For all x_13, if x_13 were a janitor, then x_13 is listening to a song. For all x_13, if x_13 reads a book, then x_13 is listening to a song.