description: You are given n integers a_1, a_2, …, a_n and an integer k. Find the maximum value of i ⋅ j - k ⋅ (a_i | a_j) over all pairs (i, j) of integers with 1 ≤ i < j ≤ n. Here, | is the [bitwise OR operator](https://en.wikipedia.org/wiki/Bitwise_operation#OR).
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 10 000) — the number of test cases.
  
  The first line of each test case contains two integers n (2 ≤ n ≤ 10^5) and k (1 ≤ k ≤ min(n, 100)).
  
  The second line of each test case contains n integers a_1, a_2, …, a_n (0 ≤ a_i ≤ n).
  
  It is guaranteed that the sum of n over all test cases doesn't exceed 3 ⋅ 10^5.
  
  Output
  
  For each test case, print a single integer — the maximum possible value of i ⋅ j - k ⋅ (a_i | a_j).
  
  Example
  
  Input
  
  
  4
  3 3
  1 1 3
  2 2
  1 2
  4 3
  0 1 2 3
  6 6
  3 2 0 0 5 6
  
  
  Output
  
  
  -1
  -4
  3
  12
  
  Note
  
  Let f(i, j) = i ⋅ j - k ⋅ (a_i | a_j).
  
  In the first test case, 
  
    * f(1, 2) = 1 ⋅ 2 - k ⋅ (a_1 | a_2) = 2 - 3 ⋅ (1 | 1) = -1. 
    * f(1, 3) = 1 ⋅ 3 - k ⋅ (a_1 | a_3) = 3 - 3 ⋅ (1 | 3) = -6. 
    * f(2, 3) = 2 ⋅ 3 - k ⋅ (a_2 | a_3) = 6 - 3 ⋅ (1 | 3) = -3. 
  
  
  
  So the maximum is f(1, 2) = -1.
  
  In the fourth test case, the maximum is f(3, 4) = 12.
solution: import java.io.*;
  import java.util.*;
  public class codeforcesB13{
  	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());
  		}
  		float nextFloat(){
  			return Float.parseFloat(next());
  		}
  	}
  	public static void main(String args[]){
  		FastReader fs=new FastReader();
  		int t=fs.nextInt();
  		while(t-->0){
  			int n=fs.nextInt();
  			int k=fs.nextInt();
  			int a[]=new int[n];
  			for(int i=0;i<n;i++){
  				a[i]=fs.nextInt();
  			}
  			long ans=(long)-1e12;
  			int min=Math.max(0,n-2*k-1);
  			for(int i=min;i<n;i++){
  				for(int j=i+1;j<n;j++){
  					ans=Math.max(ans,1l*(i+1)*(j+1)-1l*k*(a[i] | a[j]));
  				}
  			}
  			System.out.println(ans);
  		}
  	}
  }