#include <bits/stdc++.h>
using namespace std;
const long long max3 = 1003;
const long long max4 = 10004;
const long long max5 = 100005;
const long long max6 = 1000006;
const long long max7 = 10000007;
const long long lg4 = 13;
const long long lg5 = 17;
const long long lg6 = 20;
const long long INF = 2LL * 1000000000;
const long long INFLL = 9LL * 1000000000 * 1000000000;
const long long M = 1e9 + 7;
long long powmod(long long a, long long b, long long mod) {
  long long res = 1;
  a %= mod;
  for (; b; b >>= 1) {
    if (b & 1) res = (res * a) % mod;
    a = (a * a) % mod;
  }
  return res;
}
int n;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    long long n, s;
    cin >> n >> s;
    if (n == 1)
      cout << "0" << '\n';
    else if (n <= 2)
      cout << s << '\n';
    else
      cout << 2 * s << '\n';
  }
  return 0;
}

### Prompt

Generate a CPP solution to the following problem:

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.

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
const long long max3 = 1003;
const long long max4 = 10004;
const long long max5 = 100005;
const long long max6 = 1000006;
const long long max7 = 10000007;
const long long lg4 = 13;
const long long lg5 = 17;
const long long lg6 = 20;
const long long INF = 2LL * 1000000000;
const long long INFLL = 9LL * 1000000000 * 1000000000;
const long long M = 1e9 + 7;
long long powmod(long long a, long long b, long long mod) {
  long long res = 1;
  a %= mod;
  for (; b; b >>= 1) {
    if (b & 1) res = (res * a) % mod;
    a = (a * a) % mod;
  }
  return res;
}
int n;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    long long n, s;
    cin >> n >> s;
    if (n == 1)
      cout << "0" << '\n';
    else if (n <= 2)
      cout << s << '\n';
    else
      cout << 2 * s << '\n';
  }
  return 0;
}

```