Consider the following premises. forall y: U_2(y) -> S(y). exists y: S(y) -> U_2(y). Can we infer exists y: U_2(y) -> S(y) from them?
 From exists y: S(y) -> U_2(y), forall y: U_2(y) -> S(y) we can infer exists y: S(y) <-> U_2(y). Finally, from exists y: S(y) <-> U_2(y) we can infer exists y: U_2(y) -> S(y). Therefore, the answer is yes.