Potion Mixing

You are given a list of integers representing the volumes of different potion ingredients. Your task is to find the maximum total volume of two ingredients that can be mixed together while ensuring that the mixed volume does not exceed a given threshold. You need to return the maximum sum of any two distinct ingredients that satisfies the constraint. Input: - The first line contains a single integer N (1 ≤ N ≤ 1000), the number of ingredients. - The second line contains N space-separated integers denoting the volumes of the ingredients. - The third line contains a single integer T (1 ≤ T ≤ 10000), the threshold volume. Output: - Print the maximum total volume of any two distinct ingredients, or -1 if no such pair exists. Example: Input: 5 10 15 3 7 8 20 Output: 18