Minimum Operations to Make Strings Equal

Given two strings, A and B, consisting of lowercase English letters, determine the minimum number of pre-processing moves required to make string A equal to string B using the following operations:

1. Choose any index i (0 <= i < n) and swap characters a[i] and b[i].
2. Choose any index i (0 <= i < n) and swap characters a[i] and a[n-i-1].
3. Choose any index i (0 <= i < n) and swap characters b[i] and b[n-i-1].

In one pre-processing move, you can replace a character in A with any other character of the English alphabet.

Input:

The first line contains an integer T representing the number of test cases. Each test case consists of two lines:
First line: String A
Second line: String B

Output:

For each test case, output a single integer denoting the minimum number of pre-processing moves required to make string A equal to string B. Print -1 if it's impossible to achieve this. Output should be on a separate line for each test case.

Example:

Suppose T = 1, A = "abc", and B = "bca". The output should be:

2

Explanation: Two pre-processing moves can be performed to change 'a' to 'b' and 'c' to 'a'.

Constraints:

• 1 <= T <= 100
• 1 <= N <= 5000

Note:

• No pre-processing moves can be applied to string B.
• You must initiate conversion only with pre-processing operations; no further changes post these moves.