using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {

    static int[] maxTransform(int[] A)
        {
            var B = new List<int>();

            for (long k = 0, n = A.Length; k < n; k++)
            {
                for (long i = 0, o = A.Length - k; i < o; i++)
                {
                    var j = i + k;

                    var numEls = j - i + 1;
                    int[] c = new int[numEls];

                    for (var x = 0; x < numEls; x++)
                    {
                        c[x] = A[i + x];
                    }

                    B.Add(c.Max());
                }
            }

            return B.ToArray();
        }

        static Int64 solve(Int32[] A)
        {
            var B = maxTransform(A);
            var C = maxTransform(B);
            Int64 sum = 0;

            for (long i = 0, j = C.Length; i < j; i++)
            {
                sum += C[i];
            }

            return sum;
        }

    static void Main(String[] args) {
        int n = Convert.ToInt32(Console.ReadLine());
        string[] a_temp = Console.ReadLine().Split(' ');
        Int32[] a = Array.ConvertAll(a_temp,Int32.Parse);
        Int64 result = solve(a);
        Console.WriteLine(result);
    }
}