Translate the following inference to logic notation: For all x, if x_4 drives a car, then x_4 is playing squash. For all x, x_4 will not write a letter or x_4 will sleep. There is at least one x for which x_4 will not play squash. For all x, x_4 will write a letter or x_4 will drive a car. Therefore there is at least one x for which x_4 will sleep.
forall x: P(x) -> Q(x). forall x: ~R(x) or S(x). exists x: ~Q(x). forall x: R(x) or P(x). Therefore exists x: S(x).