Sets Within Sets

Problem description We know that if the set has N elements then its set of Subset has 2^N (2 to power N) elements. For example: If set has 3 elements then its set of subsets has total 2^3 (i.e. 2x2x2) elements, i.e. 8 elements. Let Consider our set is A={a,b}, Then set of Subset S = {phi, {a},{b},{a,b}} i.e. total 4 elements. Your job is to solve this problem by using an integer variable. We