#include<bits/stdc++.h>
using namespace std;
const int N=1e4+10;
long long n,a[N],maxx=-1,z;
long long dfs(long long x,long long c,long long ge,long long &z);
int main()
{
    freopen("xor_equ.in","r",stdin);
    freopen("xor_equ.out","w",stdout);
    cin>>n;
    for(long long i=1;i<=n;++i)
    {
        cin>>a[i];
    }
    for(long long i=1;i<=n;++i)
    {
        for(long long j=1;j<=n-i+1;++j)
        {
            maxx=max(maxx,dfs(i,1,j,z));
        }
    }
    cout<<maxx;
}
long long dfs(long long x,long long c,long long ge,long long &z)
{
    if(c==x)
    {
        return a[ge];
    }
    for(long long i=1;i<=x;++i)
    {
        
        z=a[ge]^dfs(x,c+1,i+ge,z);
        maxx=max(maxx,z);
    } 
}