#!/bin/python

import sys

def solve(a):
    #  Return the sum of S(S(A)) modulo 10^9+7.
    B=[]
    for k in range(len(a)):
        for i in range(len(a)-k):
            j=i+k
            if(len(a[i:j+1])>0):
                B.append(max(a[i:j+1]))
    C=[]
    for k in range(len(B)):
        for i in range(len(B)-k):
            j=i+k
            if(len(B[i:j+1])>0):
                C.append(max(B[i:j+1]))
    return sum(C)

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