An intern at HackerRank is assigned to finding the optimal middle subsequence. An optimal middle subsequence is the subsequence chosen of length $3$ chosen from an array arr, such that chosen$[0]<$ chosen$[1]>$ chosen$[2]$ and that the sum of its elements is the minimum possible. Given an array, return the sum of the values of the optimal middle subsequence. If there is none, return $-1.$