#!/bin/python

import sys

def solve(A):
    #  Return the sum of S(S(A)) modulo 10^9+7.
    s=0
    B=[]
    for k in range(0,len(A)):
        for i in range(0,len(A)-k):
            j=i+k
            c=max(A[i:j+1])
            B.append(c)
    A=[]
    A=B
    B=[]
    for k in range(0,len(A)):
        for i in range(0,len(A)-k):
            j=i+k
            c=max(A[i:j+1])
            B.append(c) 
    for k in range(len(B)):
        s+=B[k]
    return s
if __name__ == "__main__":
    n = int(raw_input().strip())
    a = map(int, raw_input().strip().split(' '))
    result = solve(a)
    print result