B'You wanted to write a text t consisting of m lowercase Latin letters. But instead, you have written a text s consisting of n lowercase Latin letters, and now you want to fix it by obtaining the text t from the text s . Initially, the cursor of your text editor is at the end of the text s (after its last character). In one move, you can do one of the following actions: Your task is to calculate the minimum number of moves required to obtain the text t from the text s using the given set of actions, or determine it is impossible to obtain the text t from the text s . You have to answer T independent test cases. The first line of the input contains one integer T ( 1 <= T <= 5000 ) -- the number of test cases. Then T test cases follow. The first line of the test case contains two integers n and m ( 1 <= m <= n <= 5000 ) -- the length of s and the length of t , respectively. The second line of the test case contains the string s consisting of n lowercase Latin letters. The third line of the test case contains the string t consisting of m lowercase Latin letters. It is guaranteed that the sum of n over all test cases does not exceed 5000 ( sum n <= 5000 ). For each test case, print one integer -- the minimum number of moves required to obtain the text t from the text s using the given set of actions, or -1 if it is impossible to obtain the text t from the text s in the given test case. '...