What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_15, x_15 will drive a car. For all x_15, x_15 will write a letter or x_15 is not a carpenter. For all x_15, if x_15 were a janitor, then x_15 is not driving a car. There is at least one x_15 for which x_15 is a janitor if and only if x_15 will write a letter. For all x_15, if x_15 writes a letter, then x_15 is a carpenter.
For all x_15, x_15 is not a janitor. For all x_15, if x_15 were a carpenter, then x_15 is writing a letter. There is at least one x_15 for which if x_15 were a janitor, then x_15 is writing a letter. There is at least one x_15 for which if x_15 writes a letter, then x_15 is a janitor.