在一个标准8×8的国际象棋棋盘上，棋盘中有些格子是可能有障碍物的。已知骑士的初始位置和目标位置，你的任务是计算出骑士最少需要多少步可以从初始位置到达目标位置。有障碍物的格子当然不可能到达。

-At a standard 8 × 8 on the international chessboard, checkerboard lattice, some are likely to have obstructions. Cavalier known initial position and target location, the mission you are required to calculate the number of step-by-step Cavalier at least from the initial position to reach the goal. There is of course impossible obstacle lattice arrival.