trie树
#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
int n,cnt,A[400005],F[400005],ch[15000005][2],Suml[400005],Sumr[400005];
void insert(int x){
int now=0;
for (int i=30; i>=0; i--){
int X=(x&(1<<i))>>i;
if (!ch[now][X]) ch[now][X]=++cnt;
now=ch[now][X];
}
}
void solve(){
cnt=0;
memset(ch,0,sizeof(ch));
memset(F,0,sizeof(F));
insert(0);
for (int i=1; i<=n; i++){
insert(A[i]);
int now=0;
for (int j=30; j>=0; j--){
int x=(A[i]&(1<<j))>>j;
if (ch[now][x^1]){
now=ch[now][x^1];
F[i]+=(1<<j);
}
else now=ch[now][x];
}
}
}
int main(){
scanf("%d",&n);
for (int i=1; i<=n; i++) scanf("%d",&A[i]);
for (int i=1; i<=n; i++) A[i]^=A[i-1];
solve();
for (int i=1; i<=n; i++) Suml[i]=F[i];
for (int i=1; i<=n/2; i++) swap(A[i],A[n-i+1]);
solve();
for (int i=1; i<=n; i++) Sumr[i]=F[n-i+1];
for (int i=1; i<=n; i++) Suml[i]=max(Suml[i],Suml[i-1]);
for (int i=n; i>=1; i--) Sumr[i]=max(Sumr[i],Sumr[i+1]);
int ans=0;
for (int i=1; i<=n; i++) ans=max(ans,Suml[i]+Sumr[i]);
printf("%d
",ans);
return 0;
}