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.InputStreamReader;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        
        StringTokenizer st = new StringTokenizer(br.readLine());
        int t = Integer.parseInt(st.nextToken());
        
        StringBuilder sb = new StringBuilder();

        while (t != 0) {
            int[] ar=new int[t];
            st = new StringTokenizer(br.readLine());
            for(int i=0;i<t;i++){
                ar[i]=Integer.parseInt(st.nextToken());
            }
            
            Stack<Integer> stack=new Stack<>();
            
            int maxXor=-1;
            
            for(int i=0;i<t;i++){
                if(stack.size()!=0){
                    while(stack.size()!=0 && stack.peek()<ar[i]){
                        int val=stack.pop();
                        int curr=ar[i]^val;
                        maxXor=Math.max(curr,maxXor);
                    }
                    if(stack.size()!=0){
                        int val=stack.peek();
                        int curr=ar[i]^val;
                        maxXor=Math.max(curr,maxXor);
                    }
                }
                stack.push(ar[i]);
            }
            sb.append(maxXor);
            t=0;
        }
        System.out.println(sb);
    }
    
    public static void swap(int[] ar,int i,int j){
        int temp=ar[i];
        ar[i]=ar[j];
        ar[j]=temp;
    }
    
    public static class Pair{
        int x;
        int y;
        
        Pair(int x,int y){
            this.x=x;
            this.y=y;
        }
        
        public int getX(){
            return x;
        }
        
        public int getY(){
            return y;
        }
    }
}
