Minimum Knight Moves

In a standard chess game, the knight moves in an "L" shape: two squares in one direction and one in the perpendicular direction. Given an 8×8 chessboard and two positions on the board, your task is to compute the minimum number of moves required for a knight to travel from the starting position to the target position. The board positions are represented by two integers for each coordinate (x and y), where both x and y lie between 1 and 8 inclusive.

The knight's move is defined by any of the eight possible moves:

[ (2, 1),\ (1, 2),\ (-1, 2),\ (-2, 1),\ (-2, -1),\ (-1, -2),\ (1, -2),\ (2, -1) ]

It is guaranteed that the destination can always be reached with a valid sequence of moves.

inputFormat

The input is read from standard input (stdin) as a single line containing four integers separated by spaces:

• start_x: the starting x-coordinate (1 ≤ start_x ≤ 8),
• start_y: the starting y-coordinate (1 ≤ start_y ≤ 8),
• end_x: the target x-coordinate (1 ≤ end_x ≤ 8),
• end_y: the target y-coordinate (1 ≤ end_y ≤ 8).

outputFormat

The output is a single integer printed to standard output (stdout), representing the minimum number of moves required for the knight to reach the destination.

1 1 8 8

6