#!/bin/python3

import sys

def solve(A, strike):
    #  Return the sum of S(S(A)) modulo 10^9+7.
    B = []
    for k in range(0, len(A)):
        for i in range(0, len(A)-k):
            j = i + k 
            tmpMax = 0
            for a0 in range(i,j+1):
                if A[a0]>tmpMax:
                    tmpMax = A[a0]
            B.append(tmpMax)
    if strike == 0:
        solve(B, 1)
    else:
        print(sum(B))

if __name__ == "__main__":
    n = int(input().strip())
    A = list(map(int, input().strip().split(' ')))
    solve(A, 0)