JZOI 4163

#include<bits/stdc++.h> 
#define N 100007
using namespace std;
int n,a[N],p[37],ans,ans3;
signed main () {
    freopen("a.in","r",stdin);
    scanf("%d",&n);
    for (int i=1;i<=n;i++) scanf("%d",a+i),ans^=a[i];

    for (int i=1;i<=n;i++) {
        for (int j=30;~j;j--) if (a[i]&(1<<j)){
            if (!p[j]) {p[j]=a[i]; break;}
            a[i]^=p[j];
        }
    }
    ans3=0;
    for (int j=30;~j;j--) {
        if ((ans >>j)&1) continue;
        if ((ans3>>j)&1) continue;
        ans3^=p[j];
    }
     printf("%d\n",ans3&((1<<31)-ans-1));
}