Chessboard Operations Simulator

Implement a class Chessboard to manage an 8x8 chessboard. The board is initially empty, represented by the character . in every cell. You must support the following operations:

• place x y S: Place the piece (character S) at coordinates (x, y).
• remove x y: Remove any piece at position (x, y) (i.e. set it to .).
• move x1 y1 x2 y2: Move a piece from position (x1, y1) to (x2, y2). After moving, the original cell becomes empty.
• piece x y: Output the piece at position (x, y). If the cell is empty, output empty.
• display: Print the entire board. Each of the 8 rows should be printed on a new line, with no spaces between characters.

All coordinates are 0-indexed with 0 ≤ x, y ≤ 7.

Input Format: The first line of input contains an integer N representing the number of operations. The following N lines each contain one of the commands described above.

Output Format: For each command that requires output (piece and display), output the result immediately. For a piece command, output a single line with the result. For a display command, output 8 lines representing the board state.

Note: The operations will be processed in the order they appear. Make sure your solution reads input from stdin and writes output to stdout.

Mathematically, if you denote the board as a matrix B with indices from 0 to 7, then for a placement operation:

$$B_{x,y} = S,$$

and for removal:

$$B_{x,y} = \text{'.'}.$$

inputFormat

The first line of input contains an integer N (the number of operations). Each of the next N lines contains one command. The commands are:

• place x y S : Place a piece denoted by character S at coordinates (x, y).
• remove x y : Remove the piece at coordinates (x, y).
• move x1 y1 x2 y2 : Move the piece from (x1, y1) to (x2, y2).
• piece x y : Output the contents at (x, y).
• display : Print the full chessboard (8 lines, each with 8 characters).

outputFormat

For each piece command, output a single line containing the piece at that cell or empty if no piece is present. For each display command, print 8 lines representing the chessboard where each line is a row of the board.

## sample

3
place 0 1 K
piece 0 1
display

K
.K......
........
........
........
........
........
........
........

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