# O(N!)愚直
n=int(input())
a=list(map(int,input().split()))
from itertools import permutations
ans=0
for aa in permutations(a,n):
    b=[]
    for i in range(n-1):
        b.append(aa[i]^aa[i+1])
    m=b[0]
    for i in range(1,n-1):
        m^=b[i]
    ans=max(ans,m)
print(ans)