import sys

n = int(input())
a = list(map(int, input().split()))
print(a)
max_xor_sum = 0
curr_xor = 0

for ci, ce in enumerate(a):
    if ci == 0:
        curr_xor = ce
    else:
        if curr_xor ^ ce > curr_xor + ce:
            # print(ci)
            curr_xor ^= ce
        else:
            max_xor_sum += curr_xor
            # print(max_xor_sum)
            curr_xor = ce

max_xor_sum += curr_xor
print(max_xor_sum)