Lina is playing with $n$ cubes placed in a row. Each cube has an integer from $1$ to $n$ written on it. Every integer from $1$ to $n$ appears on exactly one cube.
Initially, the numbers on the cubes from left to right are $a_1, a_2, \ldots, a_n$. Lina wants the numbers on the cubes from left to right to be $b_1, b_2, \ldots, b_n$.
Lina can swap any two adjacent cubes, but only if the difference between the numbers on them is at least $2$. This operation can be performed at most $20\,000$ times.
Find any sequence of swaps that transforms the initial configuration of numbers on the cubes into the desired one, or report that it is impossible.
The first line contains a single integer $n$--- the number of cubes ($1 \le n \le 100$).
The second line contains $n$ distinct integers $a_1, a_2, \ldots, a_n$--- the initial numbers on the cubes from left to right ($1 \le a_i \le n$).
The third line contains $n$ distinct integers $b_1, b_2, \ldots, b_n$--- the desired numbers on the cubes from left to right ($1 \le b_i \le n$).
If it is impossible to obtain the desired configuration of numbers on the cubes from the initial one, print a single integer $-1$.
Otherwise, in the first line, print a single integer $k$~--- the number of swaps in your sequence ($0 \le k \le 20\,000$).
In the second line, print $k$ integers $s_1, s_2, \ldots, s_k$ describing the operations in order ($1 \le s_i \le n - 1$). Integer $s_i$ stands for "swap the $s_i$-th cube from the left with the $(s_i + 1)$-th cube from the left".
You do not have to find the shortest solution. Any solution satisfying the constraints will be accepted.
5 1 3 5 2 4 3 5 1 4 2
\n · · · · \n · · · · \n
3 1 2 4
\n · · \n
In the first example test, the configuration of numbers changes as follows:
$1 \underline{3\ 5}$ $2$ $4$ , $\rightarrow$ , $\underline{1\ 5}$ $3$ $2$ $4$, $\rightarrow$ , $5$ $\underline{1\ 3}$ $2$ $4$ , $\rightarrow$ , $5$ $3$ $1$ $\underline{2\ 4}$ , $\rightarrow$ , $\underline{5\ 3}$ $1$ $4$ $2$ , $\rightarrow$, $3$ $5$ $1$ $4$ $2$
In the second example test, making even a single swap in the initial configuration is impossible.