Bike loves looking for the second maximum element in the sequence. The second maximum element in the sequence of distinct numbers x1, x2, ..., xk (k > 1) is such maximum element xj, that the following inequality holds: <image>.

The lucky number of the sequence of distinct positive integers x1, x2, ..., xk (k > 1) is the number that is equal to the bitwise excluding OR of the maximum element of the sequence and the second maximum element of the sequence.

You've got a sequence of distinct positive integers s1, s2, ..., sn (n > 1). Let's denote sequence sl, sl + 1, ..., sr as s[l..r] (1 ≤ l < r ≤ n). Your task is to find the maximum number among all lucky numbers of sequences s[l..r].

Note that as all numbers in sequence s are distinct, all the given definitions make sence.

Input

The first line contains integer n (1 < n ≤ 105). The second line contains n distinct integers s1, s2, ..., sn (1 ≤ si ≤ 109).

Output

Print a single integer — the maximum lucky number among all lucky numbers of sequences s[l..r].

Examples

Input

5
5 2 1 4 3


Output

7


Input

5
9 8 3 5 7


Output

15

Note

For the first sample you can choose s[4..5] = {4, 3} and its lucky number is (4 xor 3) = 7. You can also choose s[1..2].

For the second sample you must choose s[2..5] = {8, 3, 5, 7}.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Stack;
import java.util.StringTokenizer;

public class Main
{
    public static void main(String[] args)
    {
        CP sc =new CP();
        int n = sc.nextInt();
        int[] A = new int[n];
        for(int i=0;i<n;i++)
            A[i] = sc.nextInt();
        Stack<Integer> st = new Stack<>();
        long res=0;
        for(int i=0;i<n;i++){
            while(!st.isEmpty()){
                if(st.peek()<A[i])
                   res = Math.max(res, st.pop()^A[i]);
                else{
                    res = Math.max(res, st.peek()^A[i]);
                    break;
                }
            }
            st.push(A[i]);
        }
        System.out.println(res);
    }
    /*****************************************************************************/
    static class CP
    {
        BufferedReader bufferedReader;
        StringTokenizer stringTokenizer;
        public CP() {
            bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        }
        int nextInt() {
            return Integer.parseInt(NNNN());
        }
        long nextLong() {
            return Long.parseLong(NNNN());
        }
        double nextDouble() {
            return Double.parseDouble(NNNN());
        }
        String NNNN() {
            while (stringTokenizer == null || !stringTokenizer.hasMoreElements()) {
                try {
                    stringTokenizer = new StringTokenizer(bufferedReader.readLine());
                }
                catch (IOException  e) {
                    e.printStackTrace();
                }
            }
            return stringTokenizer.nextToken();
        }
        String nextLine() {
            String spl = "";
            try {
                spl = bufferedReader.readLine();
            }
            catch (IOException e) {
                e.printStackTrace();
            }
            return spl;
        }
    }
    /*****************************************************************************/
}