Solve the programming task below in a Python markdown code block.
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Given an array $A$ of size $N$. Find the maximum value of the expression $a * b + a - b$ where $a$ and $b$ are $2$ distinct elements of the array.

------ Input: ------

First line will contain $T$, number of testcases. Then the testcases follow. 
Each testcase contains of two lines of input.
First line will contain $N$, number of elements of the array. 
Second line contains $N$ space separated integers, elements of the array $A$. 

------ Output: ------
For each testcase, output in a single line answer to the problem.

------ Constraints  ------
$1 ≤ T ≤ 20$
$2 ≤ N ≤ 10^{5}$
$-10^{9} ≤ A_{i} ≤ 10^{9}$

----- Sample Input 1 ------ 
2

2   

2 2

3

5 3 2
----- Sample Output 1 ------ 
4

17
----- explanation 1 ------ 
Case 1: Only possible pair is $[2, 2]$ for which answer = $2 * 2 + 2 - 2$ = $4$.

Case 2: There are six possible pairs. 

For pairs $[2, 3]$ and $[3, 2]$, answer = $2 * 3 + max(2 - 3, 3 - 2)$ = $7$

For pairs $[3, 5]$ and $[5, 3]$ answer = $5 * 3 + max(3 - 5, 5 - 3)$ = $17$ and 

For the pairs $[2, 5]$ and $[5, 2]$, answer = $2 * 5 + max(2 - 5, 5 - 2)$ = $13$. 

So final answer is maximum of $\{7, 17, 13\}$ = $17$.