What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one x_18 for which if x_18 listens to a song, then x_18 is working. For all x_18, x_18 is bored or x_18 will listen to a song. For all x_18, x_18 will not work or x_18 will drink water. For all x_18, if x_18 were bored, then x_18 is working. For all x_18, if x_18 drinks water, then x_18 is writing a letter. For all x_18, x_18 is a janitor if and only if x_18 will write a letter.
There is at least one x_18 for which x_18 will work. For all x_18, if x_18 were a janitor, then x_18 is writing a letter. For all x_18, if x_18 writes a letter, then x_18 is a janitor.