#!/bin/ruby

def s(a)
  b = []
  ll = a.length
  (0..ll-1).each do |k|
    (0..ll-k-1).each do |i|
      j = i + k
      b << a[i..j].max
    end
  end
  b
end

def solve(a)
  s(s(a)).sum
end

n = gets.strip.to_i
a = gets.strip
a = a.split(' ').map(&:to_i)
result = solve(a)
puts result