Given an array A having N distinct integers.

The power of the array is defined as:

• $max(A[i]-A[j]) \space where \space 2 \le i \le N$
• for each i, j is the largest index less than i such that $A[j] < A[i]$.

Let's say the array is {1,2,5}, then the power of the array is $max((2-1), (5-2))$ , which simplifies to $max(1,3)$ which is equal to 3.

Operation Allowed:
If you are allowed to choose any two indices x and y and swap $A[x]$ and $A[y]$, find out the maximum power that can be achieved.

Note: You are allowed to perform the above operation at most once.

Input:
First line consists of a single integer, T, denoting the number of test cases.
First line of each test case consists of a single integer, denoting N.
Second line of each test case consists of N space separated integers denoting the array A.

Output:
For each test case, print the maximum achievable power on a new line.

Constraints:
$1 \le T \le 10$
$2 \le N \le 10^5$
$1 \le A[i] \le 10^9$