B"You are given a table a of size 2 x n (i.e. two rows and n columns) consisting of integers from 1 to n . In one move, you can choose some column j ( 1 <= j <= n ) and swap values a_{1, j} and a_{2, j} in it. Each column can be chosen no more than once. Your task is to find the minimum number of moves required to obtain permutations of size n in both first and second rows of the table or determine if it is impossible to do that. You have to answer t independent test cases. Recall that the permutation of size n is such an array of size n that contains each integer from 1 to n exactly once (the order of elements doesn't matter). The first line of the input contains one integer t ( 1 <= t <= 2 cdot 10^4 ) -- the number of test cases. Then t test cases follow. The first line of the test case contains one integer n ( 1 <= n <= 2 cdot 10^5 ) -- the number of columns in the table. The second line of the test case contains n integers a_{1, 1}, a_{1, 2}, ... , a_{1, n} ( 1 <= a_{1, i} <= n ), where a_{1, i} is the i -th element of the first row of the table. The third line of the test case contains n integers a_{2, 1}, a_{2, 2}, ... , a_{2, n} ( 1 <= a_{2, i} <= n ), where a_{2, i} is the i -th element of the second row of the table. It is guaranteed that the sum of n does not exceed 2 cdot 10^5 ( sum n <= 2 cdot 10^5 ). For each test case print the answer: -1 if it is impossible to obtain permutation of size n in both first and the second rows of the table, or one integer k in the first line, where k is the minimum number of moves required to obtain permutations in both rows, and k distinct integers pos_1, pos_2, ... , pos_k in the second line ( 1 <= pos_i <= n ) in any order -- indices of columns in which you need to swap "...