9. [3 marks] A set S of n positive integers is said to be splittable if it can be partitioned into two subsets such that the sum of the elements in each subset is the same. For example, S = {3, 7, 8, 9, 11} is splittable since we have can form disjoint subsets S1 = {3, 7, 9} and S2 = {8, 11} such that S1 ? S2 = S and the sum of each subset is the same (19). Prove that the following language is decidable with a high-level algorithmic description: {S | S is a set of positive integers that is splittable}.