#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'

const int M = 1e5 + 5, mod = 1e9 + 7;
int tr[M*33][2],  tot;

void insert(int x)
{
    int now = 0;
    for (int i = 31; i >= 0; i--)
    {
        int j = x >> i & 1;
        if (!tr[now][j])
            tr[now][j] = ++tot;
        now = tr[now][j];
    }
}
int query(int x)
{
    int now = 0, ans = 0;
    for (int i = 31; i >= 0; --i)
    {
        int j = x >> i & 1;
        if (j == 1)
        {
            if (tr[now][0])
            {
                now = tr[now][0];
                ans += (1 << i);
            }
            else
            {
                now = tr[now][1];
            }
        }
        else
        {
            if (tr[now][1])
            {
                now = tr[now][1];
                ans += (1 << i);
            }
            else
            {
                now = tr[now][0];
            }
        }
    }
    return ans;
}

void solve()
{
    int n;
    cin >> n;
    int ans = 0;
    while (n--)
    {
        int x;
        cin >> x;
        insert(x);
        ans = max(ans, query(x));
    }
    cout << ans << endl;
}
signed main()
{
    ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
    int t = 1;
    // cin >> t;
    while (t--)
        solve();
    return 0;
}