C. Double Sorttime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou are given two arrays a and b, both consisting of n integers.In one move, you can choose two indices i and j (1 \le i, j \le n; i \neq j) and swap a_i with a_j and b_i with b_j. You have to perform the swap in both arrays.You are allowed to perform at most 10^4 moves (possibly, zero). Can you make both arrays sorted in a non-decreasing order at the end? If you can, print any sequence of moves that makes both arrays sorted.InputThe first line contains a single integer t (1 \le t \le 100) — the number of testcases.The first line of each testcase contains a single integer n (2 \le n \le 100) — the number of elements in both arrays.The second line contains n integers a_1, a_2, \dots, a_n (1 \le a_i \le n) — the first array.The third line contains n integers b_1, b_2, \dots, b_n (1 \le b_i \le n) — the second array.OutputFor each testcase, print the answer. If it's impossible to make both arrays sorted in a non-decreasing order in at most 10^4 moves, print -1. Otherwise, first, print the number of moves k (0 \le k \le 10^4). Then print i and j for each move (1 \le i, j \le n; i \neq j).If there are multiple answers, then print any of them. You don't have to minimize the number of moves.ExampleInput
3
2
1 2
1 2
2
2 1
1 2
4
2 3 1 2
2 3 2 3
Output
0
-1
3
3 1
3 2
4 3

3
2
1 2
1 2
2
2 1
1 2
4
2 3 1 2
2 3 2 3

0 -1 3 3 1 3 2 4 3 
['implementation', 'sortings', '*1200']