#!/bin/python3

import sys

def max_transform(A):
    B = []
    sum = 0
    for k in range(len(A)):
        for i in range(len(A) - k):
            j = i + k + 1
            try:
                m = (max(A[i:j]))
                B.append(m)
                sum += m
            except:
                pass
    return B, sum

def solve(A):
    (B, sum) = max_transform(A)
    (B, sum) = max_transform(B)
    return sum


if __name__ == "__main__":
    n = int(input().strip())
    a = list(map(int, input().strip().split(' ')))
    result = solve(a)
    print(result)