#include<bits/stdc++.h>
using namespace std;

#define int long long

class Node
{
public:
    Node * child[2];
    Node()
    {
        child[0] = NULL;
        child[1] = NULL;
    }
};

// time complexity  = N * log2(max(A[i]))

void insert(Node * root, int x)
{
    for(int i = 32; i >= 0; i--)
    {
        int bit = ((x >> i) & 1);
        if(root -> child[bit] == NULL)
        {
            root -> child[bit] = new Node();
        }
        root = root -> child[bit];
    }
}

//time complexity  = N * log2(max(A[i]))

int maXxor(Node * root, int y)
{
    int ret = 0;
    for(int i = 32; i >= 0; i--)
    {
        int bit = ((y >> i) & 1);
        if(root -> child[bit ^ 1] == NULL)
        {
            root = root -> child[bit];
        }
        else
        {
            ret |= (1LL << i);
            root = root -> child[bit ^ 1];
        }
    }
    return ret;
}

// space complexity is nlogn;

int32_t main()
{
    int n;
    cin >> n;
    vector<int> arr(n);
    Node * root = new Node();
    int ans = 0;
    for(int i = 0; i < n; i++)
    {
        cin >> arr[i];
        int y = arr[i];
        insert(root, arr[i]);
        int temp = maXxor(root, y);
        ans = max(ans, temp);
    }
    cout << ans << endl;
}