You are given an array $A$ of $N$ positive and pairwise distinct integers. 
You can permute the elements in any way you want. 
The cost of an ordering $(A_1, A_2, \ldots, A_N)$ is defined as $ (((A_1 \bmod A_2) \bmod A_3)......) \bmod A_N$ where $X \bmod Y$ means the remainder when $X$ is divided by $Y$. 
You need to find the maximum cost which can be attained through any possible ordering of the elements.
-----Input:-----
- The first line contains $T$ denoting the number of test cases.
- The first line of each testcase contains a single integer $N$. 
- The second line of each testcase contains $N$ space-separated integers, the elements of $A$. 
-----Output:-----
- For each testcase, output the maximum possible cost in a new line. 
-----Constraints-----
- $1 \leq T \leq 5*10^5$
- $2 \leq N \leq 5*10^5$
- $1 \leq A_i  \leq 10^9$
- Sum of $N$ over all testcases is less than or equal to $10^6$
- All elements in a single testcase are distinct.
-----Subtasks-----
- 100 points : Original constraints.
-----Sample Input:-----
1
2
7 12
-----Sample Output:-----
7
-----Explanation:-----
The two possible ways to order the elements are [7, 12] and [12, 7]. In the first case, the cost is $7 \bmod 12 = 7$ and in the second case the cost is $12 \bmod 7 = 5$. Clearly the answer is 7.
for i in range(int(input())):
 n=int(input())
 l=list(map(int,input().split()))
 print(min(l))
for i in range(int(input())):
 n=int(input())
 l=list(map(int,input().split()))
 print(min(l))