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.
//package Codeforces.CF735;


import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.StringTokenizer;

public class B {

    static final long mod = (long) 1e9 + 7l;

    private static void solve(int t) {
        int n = fs.nextInt();
        int k = fs.nextInt();
        Pair[] pairs = new Pair[n];
        for (int i = 0; i < n; i++) {
            pairs[i] = new Pair(fs.nextInt(), i);
        }
        Arrays.sort(pairs);
//        for (int i = 0; i < n; i++) {
//            System.out.println(pairs[i].toString());
//        }
        long ans = Integer.MIN_VALUE;
        for (int i = 0; i < n - 1; i++) {
            long res = ((1 + pairs[i].b) * (1 + pairs[i + 1].b)) - k * (pairs[i].a | pairs[i + 1].a);
            ans = Math.max(ans, res);
        }
        System.out.println(ans);

    }

    static class Pair implements Comparable<Pair> {
        long a;
        long b;

        Pair(long a, long b) {
            this.a = a;
            this.b = b;
        }

        @Override
        public String toString() {
            return "Pair{" +
                    "a=" + a +
                    ", b=" + b +
                    '}';
        }

        public int compareTo(Pair p) {
            return (int) a - (int) p.a;
        }
    }

    public static void main(String[] args) {
        fs = new FastScanner();
        out = new PrintWriter(System.out);
        long s = System.currentTimeMillis();
        int t = fs.nextInt();
        for (int i = 1; i <= t; i++) solve(t);
        out.close();
//        System.err.println( System.currentTimeMillis() - s + "ms" );
    }

    static boolean DEBUG = true;
    static PrintWriter out;
    static FastScanner fs;

    static void trace(Object... o) {
        if (!DEBUG) return;
        System.err.println(Arrays.deepToString(o));
    }

    static void pl(Object o) {
        out.println(o);
    }

    static void p(Object o) {
        out.print(o);
    }

    static long gcd(long a, long b) {
        return (b == 0) ? a : gcd(b, a % b);
    }

    static int gcd(int a, int b) {
        return (b == 0) ? a : gcd(b, a % b);
    }

    static void sieveOfEratosthenes(int n, int factors[]) {
        factors[1] = 1;
        for (int p = 2; p * p <= n; p++) {
            if (factors[p] == 0) {
                factors[p] = p;
                for (int i = p * p; i <= n; i += p)
                    factors[i] = p;
            }
        }
    }

    static long mul(long a, long b) {
        return a * b % mod;
    }

    static long fact(int x) {
        long ans = 1;
        for (int i = 2; i <= x; i++) ans = mul(ans, i);
        return ans;
    }

    static long fastPow(long base, long exp) {
        if (exp == 0) return 1;
        long half = fastPow(base, exp / 2);
        if (exp % 2 == 0) return mul(half, half);
        return mul(half, mul(half, base));
    }

    static long modInv(long x) {
        return fastPow(x, mod - 2);
    }

    static long nCk(int n, int k) {
        return mul(fact(n), mul(modInv(fact(k)), modInv(fact(n - k))));
    }

    static class FastScanner {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer("");

        public String next() {
            while (!st.hasMoreElements())
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        int[] readArray(int n) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++)
                a[i] = nextInt();
            return a;
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    }
}
