Maximizing Unique Elements in Set

You have two strings, each containing an even number of digits(0-9), called "nums1" and "nums2".

Your task is to select exactly half of the digits from "nums1" and half of the digits from "nums2". Then, you combine the selected digits and insert them into a set called "s".

Your goal is to maximize the number of unique elements in the set "s" and print the size of the set.