Given a grid, you are asked to fill it with L-shaped trominos except for a single cell (r, c). That one cell needs to be empty.
An L-shaped tromino is a figure obtained by removing a single cell from a square.
In case it’s not possible to fill the grid, the program should print Impossible.
The first line of the input contains a single integer n (1 ≤ n ≤ 9).
The second line contains the coordinates of the empty cell (r, c) (1 ≤ r, c ≤ ) where r is the row of the empty cell and c is the column.
The program should print rows that contain numbers separated by a space. Each number should represent a single L-shaped tromino. The removed cell should be marked with a 0. The trominos should be indexed from 1 to . In case there are many solutions, the program can output any of those.