Your computer engineering instructor decided to ramp things up a bit (in terms of difficulty, of course) with this next task:

Write a program to find the maximum difference between the ~XOR~ of adjacent elements of a given array.

More formally,

Given an array ~A~, find the maximum value of ~(A[i] \oplus A[i+1])-(A[j] \oplus A[j+1])~ for some ~i~ and ~j~, where ~i \neq j~.

Unimpressed by the supposed "challenge", you open up your favourite text editor and begin typing away... in assembly.

Input Specification

The first line of input will contain a single integer ~N~ ~(3 \le N \le 100)~.

The second line of input will contain ~N~ space-separated integers in the range ~[-10^3,10^3]~, denoting the contents of array ~A~.

Output Specification

The desired integer value as defined by your teacher on a line by itself.

Sample Input

3
3 2 1

Sample Output

2

Explanation

We can find the maximum value when ~i=2~ and ~j=1~:

~=(A[2] \oplus A[3])-(A[1] \oplus A[2])~

~=(2 \oplus 1)-(3 \oplus 2)~

~=2~

Note

To use libc in NASM, the first line of your program should be ; libc. For all others, it should be ; features: libc.