/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		int[] A = {2, 1, 6, 3, 5};
		int X = 7;
		int n = A.length;
 
		int[][] dp = new int[n][2]; 
 
 
		for(int i = 1; i < n; i++){
			dp[i][0] = Math.max((A[i] ^ A[i-1]) + dp[i - 1][0], (A[i] ^ (A[i-1] + X)) + dp[i - 1][1]);
			dp[i][1] = Math.max(((A[i] + X) ^ (A[i-1] + X)) + dp[i-1][1], ((A[i] + X) ^ (A[i-1])) + dp[i-1][0]);
		}
		System.out.print( Math.max(dp[n-1][0], dp[n-1][1]));
	}
}

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