What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_1, if x_1 were a janitor, then x_1 is a musician. For all x_1, x_1 is a janitor or x_1 is not a musician. There is at least one x_1 for which x_1 is not a janitor.
For all x_1, if x_1 were a musician, then x_1 is a janitor.