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 static java.lang.Math.*;

public class Decomp{
  
  public static void main(String[] args) throws IOException{
      BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
      int count = Integer.parseInt(input.readLine());
        String[] Masiv = (input.readLine().split(" "));
        int Xor = 0;
        int k=0;
        int[] Masiv2 = new int [count];
        Masiv2[0]=Integer.parseInt(Masiv[0]);
      for(int i = 1; i < count; i++){
          while(k >= 0 && Masiv2[k] < Integer.parseInt(Masiv[i])) {
                  Xor=max(Xor,Integer.parseInt(Masiv[i])^Masiv2[k]);
                  k--;
          }               
              if (k >= 0) {
                  Xor=max(Xor,Integer.parseInt(Masiv[i])^Masiv2[k]);
                  }
              Masiv2[++k]=Integer.parseInt(Masiv[i]);
     }    
      System.out.print(Xor);      
  }
}