Description: 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: - $$$a$$$ is a prefix of $$$b$$$, but $$$a \ne b$$$; - in the first position where $$$a$$$ and $$$b$$$ differ, the string $$$a$$$ has a letter that appears earlier in the alphabet than the corresponding letter in $$$b$$$. Input Format: The first line of input contains one integer $$$q$$$ ($$$1 \le q \le 10\,000$$$): the number of test cases. The first line of each test case contains a single integer $$$n$$$ ($$$1 \le n \le 10^5$$$). 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 $$$2 \cdot 10^5$$$. Output Format: 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. Note: None