#T1. 测试
测试
当前没有测试数据。
[ABC117_D] Problem Statement
Score : points
Problem Statement
You are given non-negative integers and another non-negative integer .
For a integer between and (inclusive), let XOR XOR XOR .
Here, for non-negative integers and , XOR denotes the bitwise exclusive OR of and .
Find the maximum value of .
What is XOR?
The bitwise exclusive OR of and , , is defined as follows:
- When is written in base two, the digit in the 's place ( ) is if, when written in base two, exactly one of and has in the 's place, and otherwise.
For example, XOR . (When written in base two: XOR .)
Constraints
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
$N$ $K$
$A_1$ $A_2$ $...$ $A_N$
Output
Print the maximum value of .
Sample Input 1
3 7
1 6 3
Sample Output 1
14
The maximum value is: XOR XOR XOR .
Sample Input 2
4 9
7 4 0 3
Sample Output 2
46
Sample Input 3
1 0
1000000000000
Sample Output 3
1000000000000