Papyrus came up with another puzzle for Frisk to solve. Papyrus brought two arrays (a) and (b) of length (n) and allowed the following two operations to be performed: choose any index (i) ((1 \le i \le n)) and change (a_i) to (a_i - 1). The execution time of such an operation is (1) second. reorder all elements of array (a) in any way. The execution time of such an operation is (c) seconds. You need to convert array (a) into array (b). Frisk wants to solve the puzzle as soon as possible. Help Frisk determine the minimum time needed to solve the puzzle. If there is no solution, output (-1). Each test contains multiple test cases. The first line contains the number of test cases (t) ((1 \le t \le 500)). The description of the test cases follows. The first line of each test case contains two integers (n) and (c) ((1 \le n, c \le 100)) — the length of arrays (a) and (b) and the cost of the second operation. The second line of each test case contains (n) integers (a_1, a_2, \ldots, a_n) ((1 \le a_i \le 100)) — the elements of the first array. The third line of each test case contains (n) integers (b_1, b_2, \ldots, b_n) ((1 \le b_i \le 100)) — the elements of the second array. For each test case, output a single integer representing the minimum number of seconds required to solve the puzzle, or (-1) if it is impossible to solve the puzzle. In the first test case, it is impossible to transform (a) into (b) using only subtraction because (a_2 \lt b_2). Let's rearrange the elements of array (a) as follows: (5, 2, 3 \Rightarrow 2, 3, 5). Now it is enough to subtract one from (a_3), and we get that array (a) becomes equal to array (b) in (5 + 1 = 6) seconds. In the second test case, all elements of (a) are less than all elements of (b), which means (a) cannot be transformed into (b). In the third test cas