由文件input.txt提供输入数据。输入文件第1 行有2个正整数n和m（1<=n,m<=100），

表示仓库是n×m个格子的矩形阵列。接下来有n行，每行有m个字符，表示格子的状态。

S 表示格子上放了不可移动的沉重货物；

w 表示格子空闲；

M 表示仓库管理员的初始位置；

P 表示箱子的初始位置；

K 表示箱子的目标位置。

-Provided by the input data file input.txt. Line 1 input file there are two positive integers n and m (1 < = n, m < = 100), said the warehouse is a n × m rectangular grid array. Then there are n lines, each line has m characters, said the state lattice. Lattice S that can not be put on the movement of heavy goods　w that free lattice　M said that the initial location of the warehouse manager　P said that the initial location of the box　K said that the goal of the location of the box.