Consider the following premises. r_1 -> r. s_3 or ~p. s_3 -> r_1. Can we infer p -> r from them?
 From s_3 or ~p we can infer p -> s_3. From p -> s_3, s_3 -> r_1 we can infer p -> r_1. Finally, from p -> r_1, r_1 -> r we can infer p -> r. Therefore, the answer is yes.