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:
\(1 \le T \le 10\)
\(2 \le N \le 10^5\)
\(1 \le A[i] \le 10^9\)