#include <iostream>
#include <cstdio>
using namespace std;
const int N = 1E5 + 10;
int son[N * 31][2], idx;
void insert(int t){
    int u = 0;
    for(int i = 30; i >= 0; i -- ){
        int v = t >> i & 1;
        if(!son[u][v])  son[u][v] = ++ idx;
        u = son[u][v];
    }
}
int query(int t){
    int u = 0, res = 0;
    for(int i = 30; i >= 0; i -- ){
        int v = t >> i & 1;
        if(son[u][!v]){
           u = son[u][!v];
           res = res * 2 + !v; 
        }else{
           u = son[u][v];
           res = res * 2 + v;
        }  
    }
    return res ^ t;
}
int main(){
    int n, res = 0;
    cin >> n;
    int tmp;
    for(int i = 0; i < n; i ++ ){
        cin >> tmp;
        insert(tmp);
        res = max(query(tmp), res);
    }
    cout << res << endl;
    return 0;
}