You are given two integers n and m. You have to construct the array a of length n consisting of non-negative integers (i.e. integers greater than or equal to zero) such that the sum of elements of this array is exactly m and the value ∑_{i=1}^{n-1} |a_i - a_{i+1}| is the maximum possible. Recall that |x| is the absolute value of x.

In other words, you have to maximize the sum of absolute differences between adjacent (consecutive) elements. For example, if the array a=[1, 3, 2, 5, 5, 0] then the value above for this array is |1-3| + |3-2| + |2-5| + |5-5| + |5-0| = 2 + 1 + 3 + 0 + 5 = 11. Note that this example doesn't show the optimal answer but it shows how the required value for some array is calculated.

You have to answer t independent test cases.

Input

The first line of the input contains one integer t (1 ≤ t ≤ 10^4) — the number of test cases. Then t test cases follow.

The only line of the test case contains two integers n and m (1 ≤ n, m ≤ 10^9) — the length of the array and its sum correspondingly.

Output

For each test case, print the answer — the maximum possible value of ∑_{i=1}^{n-1} |a_i - a_{i+1}| for the array a consisting of n non-negative integers with the sum m.

Example

Input


5
1 100
2 2
5 5
2 1000000000
1000000000 1000000000


Output


0
2
10
1000000000
2000000000

Note

In the first test case of the example, the only possible array is [100] and the answer is obviously 0.

In the second test case of the example, one of the possible arrays is [2, 0] and the answer is |2-0| = 2.

In the third test case of the example, one of the possible arrays is [0, 2, 0, 3, 0] and the answer is |0-2| + |2-0| + |0-3| + |3-0| = 10.
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Vector;

public class Codechef {

    public static PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));

    public static int[] radixSort(int[] f) {
        return radixSort(f, f.length);
    }

    public static int[] radixSort(int[] f, int n) {
        int[] to = new int[n];
        {
            int[] b = new int[65537];
            for (int i = 0; i < n; i++)
                b[1 + (f[i] & 0xffff)]++;
            for (int i = 1; i <= 65536; i++)
                b[i] += b[i - 1];
            for (int i = 0; i < n; i++)
                to[b[f[i] & 0xffff]++] = f[i];
            int[] d = f;
            f = to;
            to = d;
        }
        {
            int[] b = new int[65537];
            for (int i = 0; i < n; i++)
                b[1 + (f[i] >>> 16)]++;
            for (int i = 1; i <= 65536; i++)
                b[i] += b[i - 1];
            for (int i = 0; i < n; i++)
                to[b[f[i] >>> 16]++] = f[i];
            int[] d = f;
            f = to;
            to = d;
        }
        return f;
    }

    public static void main(String[] args) throws java.lang.Exception {
        // your code goes here
        Scanner ob = new Scanner(System.in);
        int T = ob.nextInt();
        for (int t = 0; t < T; t++) {
            int n = ob.nextInt();
            int m = ob.nextInt();
            int x = n / 2;
            if (n == 1) {
                out.println(0);
            } else if (n == 2) {
                out.println(m);
            } else {
                int y = m / x;
                long sum = 0;
                int check = 0;
                if (n % 2 == 0) {
                    x = x - 1;
                }

                sum = 2 * y * (x - 1);
                check = y * (x - 1);
                sum = sum + 2 * (m - check);

                out.println(sum);
            }

        }
        out.close();
    }
}
