#include<cstdio>
#include<vector>
#include<algorithm>
#include<iostream>
#include<cstring>
#include<queue>
#include<cmath>
using namespace std;
long long  c[10010];
int n;
long long a[10010];
int lowbit(int x)
{
	return x&-x;
}
void add(int x,int k)
{
	while (x<=n)
	{
		c[x]^=k;
		x+=lowbit(x);
	}
}
int sum(int x)
{
	int s=0;
	while (x>0)
	{
		s^=c[x];
		x-=lowbit(x);
	}
	return s;
}
int main()
{
	freopen("xor_equ.in","r",stdin);
	freopen("xor_equ.out","w",stdout);
	cin>>n;
	for (int i=1;i<=n;i++)
	 cin>>a[i],add(i,a[i]);
	long long ans=-1;
	for (int i=1;i<=n;i++)
	 for (int j=0;j+i<=n;j++)
	 {
	 	long long k=sum(i+j)^sum(i);
	 	ans=max(ans,k);
	 }
	for (int i=1;i<=n/2;i++)
	 for (int j=0;j+i<=n/2;j++)
	  for (int l=n/2+1;l<=n;l++)
	   for (int r=0;r+l<=n;r++)
	   {
	   		long long k=sum(i+j)^sum(i)^sum(l+r)^sum(l);
	   		ans=max(ans,k);
	   }
	cout<<ans;
	return 0;
}