#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int maxn=10010;
int n;
long long v[maxn],w[maxn];
long long ans;
void cal(int x){
	long long tmp=0;
	for(int i=1;i<=x;i++){
		if(v[i])tmp^=w[i];
		ans=max(ans,tmp);
	}
}
void dfs(int x){
	if(x==n+1)return;
	v[x]=1,cal(x),dfs(x+1);
	v[x]=0,cal(x),dfs(x+1);
}
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",&w[i]);
	dfs(1);
	printf("%lld",ans);
	return 0;
}