Consider the following premises. There is at least one x_4 for which x_4 is an astronaut or x_4 is a janitor. For all x_4, x_4 is not an astronaut. For all x_4, if x_4 were a janitor, then x_4 is sad. Can we infer the following from them? For all x_4, x_4 is not sad.
 From the fact that there is at least one x_4 for which x_4 is an astronaut or x_4 is a janitor, and that for all x_4, x_4 is not an astronaut we can infer that there is at least one x_4 for which x_4 is a janitor. Finally, from the fact that for all x_4, if x_4 were a janitor, then x_4 is sad, and that there is at least one x_4 for which x_4 is a janitor we can infer that there is at least one x_4 for which x_4 is sad, which contradicts that For all x_4, x_4 is not sad. Therefore, the answer is no.