import operator
from functools import reduce
from sys import stdin, stdout
input = lambda: stdin.readline().rstrip()
write = stdout.write

def main():
    global A, Ret
    n = int(input())
    A = tuple(map(int, input().split()))

    Ret = []
    fp(n)
    print(max(Ret))

def fp(n, d=None, dd=None, idx=0):
    nh = n // 2
    if d is None:
        d = [0] * nh
    if dd is None:
        dd = [0] * n
    if idx == n:
        pwr = [0] * nh
        for i in range(n):
            pwr[dd[i]] += A[i]
        Ret.append(reduce(operator.xor, pwr))
        return

    for i in range(nh):
        if d[i] == 0:
            d[i] = 1
            dd[idx] = i
            fp(n, d, dd, idx + 1)
            d[i] = 0
            break

    for i in range(nh):
        if d[i] == 1:
            d[i] = 2
            dd[idx] = i
            fp(n, d, dd, idx + 1)
            d[i] = 1

main()