#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
long long f[10010];
long long A[10010];
int n;
long long ans=0;
inline void solve(){
	for(int i=1;i<=n;i++)
		f[i]=A[i];
	for(int i=1;i<=n;i++){
		for(int j=1;j<i;j++)
			if(f[j]^A[i]>f[i])
				f[i]=f[j]^A[i];
		ans=max(ans,f[i]);
	}
	printf("%lld\n",ans);
}
inline void dfs(int x,long long now){
	ans=max(ans,now);
	if(x==n+1)
		return ;
	dfs(x+1,now^A[x]);
	dfs(x+1,now);
}
inline void Do(){
	dfs(1,0);
	printf("%lld\n",ans);
}
int main(){
	freopen("xor_equ.in","r",stdin);
	freopen("xor_equ.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++)
		scanf("%lld",&A[i]);
	if(n<=20)
		Do();
	else if(n)
		solve();
return 0;
}