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 y_1 for which y_1 will drink water or y_1 will not take a plane. For all y_1, y_1 will take a plane if and only if y_1 will climb a mountain. For all y_1, if y_1 drinks water, then y_1 is climbing a mountain.
There is at least one y_1 for which if y_1 takes a plane, then y_1 is drinking water. For all y_1, if y_1 takes a plane, then y_1 is climbing a mountain. For all y_1, if y_1 climbs a mountain, then y_1 is taking a plane.