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 javafx.util.*;
public class abc {
	
	static int[][] graph;
	static int[] ans;

	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub
		InputReader s = new InputReader(System.in);
		PrintWriter p = new PrintWriter(System.out);
		int w=s.nextInt();
		while(w-->0) {
			long n=s.nextLong();
			long m=s.nextLong();
			if(n==1) {
				System.out.println(0);
			}else if(n==2) {
				System.out.println(m);
			}else {
				System.out.println(2*m);
			}
		}
	}
	static long power(long x, long y) 
    { 
		long temp=0l; 
        if( y == 0) 
            return 1l; 
        temp = power(x, y/2);  
          
        if (y%2 == 0) 
            return temp*temp; 
        else
        { 
            if(y > 0) 
                return x * temp * temp; 
            else
                return (temp * temp) / x; 
        } 
    }  
	
	
	public static boolean helper(int[] arr1 , int[] arr2) {
		boolean[] temp=new boolean[3];
		if(arr1.length==0) return true;
		if(arr1[0]!=arr2[0]) return false;
		temp[arr1[0]+1]=true;
		for(int i=1 ; i<arr1.length ; i++) {
			
			if(arr1[i]==arr2[i]) {
				
			}else if(arr1[i]<arr2[i]) {
				if(!temp[2]) {
					return false;
				}
			}else {
				if(!temp[0]) {
					return false;
				}
			}
			temp[arr1[i]+1]=true;
		}
		return true;
	}
	

	public static ArrayList Divisors(long n) {
		ArrayList<Long> div = new ArrayList<>();
 
		for (long i = 1; i <= Math.sqrt(n); i++) {
			if (n % i == 0) {
				div.add(i);
 
				if (n / i != i)
					div.add(n / i);
			}
		}
		return div;
	}
 
	public static int BinarySearch(long[] a, long k) {
		int n = a.length;
		int i = 0, j = n - 1;
		int mid = 0;
 
		if (k < a[0])
			return 0;
		else if (k >= a[n - 1])
			return n;
		else {
			while (j - i > 1) {
				mid = (i + j) / 2;
 
				if (k >= a[mid])
					i = mid;
				else
					j = mid;
			}
		}
 
		return i + 1;
	}
 
	public static long GCD(long a, long b) {
		if (b == 0)
			return a;
		else
			return GCD(b, a % b);
	}
 
	public static long LCM(long a, long b) {
		return (a * b) / GCD(a, b);
	}
 
	static class InputReader {
 
		private final InputStream stream;
		private final byte[] buf = new byte[8192];
		private int curChar, snumChars;
		private SpaceCharFilter filter;
 
		public InputReader(InputStream stream) {
			this.stream = stream;
		}
 
		public int snext() {
			if (snumChars == -1)
				throw new InputMismatchException();
			if (curChar >= snumChars) {
				curChar = 0;
				try {
					snumChars = stream.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (snumChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}
 
		static class pair implements Comparable<pair> {
			Integer x, y;
 
			pair(int x, int y) {
				this.x = x;
				this.y = y;
			}
 
			public int compareTo(pair o) {
				int result = x.compareTo(o.x);
				if (result == 0)
					result = y.compareTo(o.y);
 
				return result;
			}
 
			public String toString() {
				return x + " " + y;
			}
 
			public boolean equals(Object o) {
				if (o instanceof pair) {
					pair p = (pair) o;
					return p.x - x == 0 && p.y - y == 0;
				}
				return false;
			}
 
			public int hashCode() {
				return new Long(x).hashCode() * 31 + new Long(y).hashCode();
			}
		}
 
		public int nextInt() {
			int c = snext();
			while (isSpaceChar(c)) {
				c = snext();
			}
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
 
		public long nextLong() {
			int c = snext();
			while (isSpaceChar(c)) {
				c = snext();
			}
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
 
		public int[] nextIntArray(int n) {
			int a[] = new int[n];
			for (int i = 0; i < n; i++) {
				a[i] = nextInt();
			}
			return a;
		}
 
		public String readString() {
			int c = snext();
			while (isSpaceChar(c)) {
				c = snext();
			}
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = snext();
			} while (!isSpaceChar(c));
			return res.toString();
		}
 
		public String nextLine() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = snext();
			} while (!isEndOfLine(c));
			return res.toString();
		}
 
		public boolean isSpaceChar(int c) {
			if (filter != null)
				return filter.isSpaceChar(c);
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}
 
		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}
 
		public interface SpaceCharFilter {
			public boolean isSpaceChar(int ch);
		}
	}
 
	static class CodeX {
		public static void sort(long arr[]) {
			merge_sort(arr, 0, arr.length - 1);
		}
 
		private static void merge_sort(long A[], long start, long end) {
			if (start < end) {
				long mid = (start + end) / 2;
				merge_sort(A, start, mid);
				merge_sort(A, mid + 1, end);
				merge(A, start, mid, end);
			}
 
		}
 
		private static void merge(long A[], long start, long mid, long end) {
			long p = start, q = mid + 1;
			long Arr[] = new long[(int) (end - start + 1)];
			long k = 0;
 
			for (int i = (int) start; i <= end; i++) {
				if (p > mid)
					Arr[(int) k++] = A[(int) q++];
 
				else if (q > end)
					Arr[(int) k++] = A[(int) p++];
 
				else if (A[(int) p] < A[(int) q])
					Arr[(int) k++] = A[(int) p++];
 
				else
					Arr[(int) k++] = A[(int) q++];
			}
			for (int i = 0; i < k; i++) {
				A[(int) start++] = Arr[i];
			}
 
		}
 
	}
 
}


