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_17 for which x_17 is happy. For all x_17, if x_17 were an astronaut, then x_17 is working. For all x_17, x_17 is an astronaut or x_17 is sad. For all x_17, x_17 will work if and only if x_17 is sad. For all x_17, if x_17 were happy, then x_17 is a janitor.
There is at least one x_17 for which x_17 is a janitor. For all x_17, if x_17 works, then x_17 is sad. For all x_17, if x_17 were sad, then x_17 is working.