#!/bin/python3

import sys
from itertools import *

def powerset(numlist):
    N = len(numlist)
    indices = {(a, b) for (a, b) in product(range(N)+1, range(N)+1) if a < b}
    return {numlist[a:b] for (a, b) in indices}

def value(B):
    return sum(x*y for x, y in product(B, B))

def largestValue(A):
    return max({value(B) for B in powerset(A)})

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