B"You are given two strings s and t of equal length n . In one move, you can swap any two adjacent characters of the string s . You need to find the minimal number of operations you need to make string s lexicographically smaller than string t . A string a is lexicographically smaller than a string b if and only if one of the following holds: The first line of input contains one integer q ( 1 <= q <= 10 ,000 ): the number of test cases. The first line of each test case contains a single integer n ( 1 <= n <= 10^5 ). The second line of each test case contains the string s consisting of n lowercase English letters. The third line of each test case contains the string t consisting of n lowercase English letters. It is guaranteed that the sum of n over all test cases does not exceed 2 cdot 10^5 . For each test case, print in a separate line the minimal number of operations you need to make string s lexicographically smaller than string t , or -1 , if it's impossible. "...