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.*;
import java.util.*;
public class c
{ 
static PrintWriter out = new PrintWriter(System.out);


public static void main(String[] args) 
{ 
    int n = ni();
    int[] arr = new int[n];
        for (int i = 0; i < n; i++)
            arr[i] = ni();
       
        int ans = 0;
        Stack<Integer> stack = new Stack<>();
        for (int i = 0; i < n; i++) {
            int k = arr[i];
            while(!stack.isEmpty() && stack.peek() < k){
                ans = Math.max(ans, k ^ stack.peek());
                stack.pop();
            }
            if(!stack.isEmpty()){
                ans = Math.max(ans, k ^ stack.peek());
            }
            stack.push(k);
        }
   
         out.println(ans);
         out.flush();

}

static long mod = 1000000007;
static void fact(long a[]){
         a[0]=1;
         for(int i=1;i<a.length;i++)
                a[i] = (i*a[i-1])%mod;
}
static long gcd(long a,long b){

  if(b%a==0) return a;
  return gcd(b%a,a);
}
static long pow(long a,long b,long mod){

long ans=1;
while(b>0){
if(b%2==1)
    ans = (ans*a)%mod;
    b=b/2;
    a=(a*a)%mod;
}
   return ans;
}  
    static FastReader sc=new FastReader(); 
 
      static int ni(){
                 int x = sc.nextInt();
                 return(x);
        }
      static long nl(){
              long x = sc.nextLong();
              return(x);
         }
      static String n(){
                 String str = sc.next();
                     return(str);
       }
     static String ns(){
                 String str = sc.nextLine();
                   return(str);
      }
     static double nd(){
               double d = sc.nextDouble();
                 return(d);
       }
  static class FastReader 
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() 
        { 
            br = new BufferedReader(new
                     InputStreamReader(System.in)); 
        } 
  
        String next() 
        { 
            while (st == null || !st.hasMoreElements()) 
            { 
                try
                { 
                    st = new StringTokenizer(br.readLine()); 
                } 
                catch (IOException  e) 
                { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt() 
        { 
            return Integer.parseInt(next()); 
        } 
  
        long nextLong() 
        { 
            return Long.parseLong(next()); 
        } 
  
        double nextDouble() 
        { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() 
        { 
            String str = ""; 
            try
            { 
                str = br.readLine(); 
            } 
            catch (IOException e) 
            { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    } 
}