write a go solution for Description:
Little R is a magician who likes non-decreasing arrays. She has an array of length n, initially as a_1,ldots,a_n, in which each element is an integer between [1,m]. She wants it to be non-decreasing, i.e., a_1<=a_2<=ldots<=a_n.

To do this, she can perform several magic tricks. Little R has a fixed array b_1ldotsb_m of length m. Formally, let's define a trick as a procedure that does the following things in order:

- Choose a set Ssubseteq1,2,ldots,n.
- For each uinS, assign a_u with b_a_u.

Little R wonders how many tricks are needed at least to make the initial array non-decreasing. If it is not possible with any amount of tricks, print -1 instead.

Input Format:
Each test contains multiple test cases. The first line contains the number of test cases t (1<=t<=10^4). The description of the test cases follows.

The first line of each test case contains two integers n and m (1<=n<=10^6, 1<=m<=10^6) — the length of the initial array and the range of the elements in the array.

The second line of each test case contains n integers a_1,ldots,a_n (1<=a_i<=m) — the initial array.

The third line of each test case contains m integers b_1,ldots,b_m (1<=b_i<=m) — the fixed magic array.

It is guaranteed that the sum of n over all test cases does not exceed 10^6 and the sum of m over all test cases does not exceed 10^6.

Output Format:
For each test case, output a single integer: the minimum number of tricks needed, or -1 if it is impossible to make a_1,ldots,a_n non-decreasing.

Note:
In the first case, the initial array a_1,ldots,a_n is [1,6,3,7,1]. You can choose S as follows:

- first trick: S=[2,4,5], a=[1,1,3,5,2];
- second trick: S=[5], a=[1,1,3,5,3];
- third trick: S=[5], a=[1,1,3,5,5].

In the second case, it is impossible to make a_1,ldots,a_n non-decreasing.. Output only the code with no comments, explanation, or additional text.