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.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map.Entry;
import java.util.Scanner;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeMap;

public class Main {
static long result = 0;
public static void main(String[] args) {
	FastReader in=new FastReader();
	Stack<Long> stack = new Stack<Long>();
	int n=in.nextInt();
	while(n-->0) {
		long t=in.nextInt();
		while(stack.size() > 0 && stack.peek() <= t) {
			result = Math.max(result, t^stack.pop());
		}
		if(stack.size() > 0)result = Math.max(result, t^stack.peek());
		stack.push(t);
	}
	System.out.println(result);
}


public static class FastReader{
	BufferedReader br ; 
	StringTokenizer st ; 
	
	FastReader(){
		br = new BufferedReader(new InputStreamReader(System.in));
		st = null;
	}
	
	public String next(){
		if(st==null || !st.hasMoreTokens()) {
			try {
				st = new StringTokenizer(br.readLine());
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return st.nextToken();
	}
	
	public int nextInt() {
		return Integer.parseInt(next());
	}
}
}
