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.*;
import java.util.*;
import java.util.stream.Collectors;

public class Main {

    void solve() {
        int n = in.nextInt();
        int m = in.nextInt();
        if (n==1) {
            out.println(0);
        }else if(n==2) {
            out.println(m);
        }else{
            out.println(2*m);
        }
    }

    void init(){

    }

    static final boolean MULTI_TEST = true;

    // --------------------------------------------------------------------------------------------------------------
    // --------------------------------------------------HELPER------------------------------------------------------
    // --------------------------------------------------------------------------------------------------------------


    void solve2() {
        init();
        if (MULTI_TEST) {
            int t = in.nextInt();
            for (int i = 0; i < t; i++) {
                solve();
            }
        }else {
            solve();
        }
    }

    // --------------------SCANNER-------------------------
    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;

        public MyScanner(boolean debug) {
            if (debug) {
                try {
                    br = new BufferedReader(new FileReader("input.txt"));
                } catch (FileNotFoundException e) {
                    throw new RuntimeException(e);
                }
            } else {
                br = new BufferedReader(new InputStreamReader(System.in));
            }
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                st = new StringTokenizer(nextLine());
            }
            return st.nextToken();
        }

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

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

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

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            try {
                String line = br.readLine();
                if (line == null) {
                    throw new RuntimeException("empty line");
                }
                return line;
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
    }

    // --------------------WRITER-------------------------
    public static class MyWriter extends PrintWriter {

        public MyWriter(OutputStream out) {
            super(out);
        }

        void println(int[] arr) {
            String line = Arrays.stream(arr).mapToObj(String::valueOf).collect(Collectors.joining(" "));
            println(line);
        }

    }
    // --------------------MAIN-------------------------

    public MyScanner in;
    public MyWriter out;

    public static void main(String[] args) {
        Main m = new Main();
        m.in = new MyScanner(args.length > 0);
        m.out = new MyWriter(new BufferedOutputStream(System.out));
        m.solve2();
        m.out.close();
    }
}