Ashish has a secret servant named Hsrada.
Hsrada has N lanterns. Each lantern has a brightness B value associated with it. Consider all K-sized subsets of these lanterns, among all those subsets, find the maximum ambience value of the subset.
The ambience value of a subset = $\sum \mid B_i - B_j \mid \forall \ i, j \in subset, where \ i < j.$

Task
Find the maximum ambience value.

Notes

• The ambience value of a subset with 1 element is 0.
• | X - Y | represents the absolute value of (X - Y).

Example
Assumptions

• K = 2
• N = 3
• B = [11, 3, 15]

Approach

• If we choose the subset [3, 15]. We get an ambience value of ( | 3 - 15 | ) 12.
• If we choose the subset [11, 3]. We get an ambience value of ( | 11 - 3 | ) 9.
• If we choose the subset [11, 15]. We get an ambience value of ( | 11 - 15 | ) 4. 

Thus, we get the maximum ambience value of 12.

Input Format
Note: This is the input format that you must use to provide custom input (available above the Compile and Test button).

• The first line contains T representing the number of test cases.
• For each test case:
  • The first line contains K representing the number of lanterns to be chosen.
  • The second line contains N representing the number of lanterns.
  • The third line contains N integers, representing the brightness B value of the lanterns.

Output Format
For each test case, print a single integer representing the maximum ambience value.

Constraints
$1 \leq T \leq 10$
$1 \leq K \leq N \leq 2 * 10^5$
$1 \leq B_i \leq 10^9$