B"This problem has an attachment. You can use it to simulate and visualize the movements of the amoeba. Amoeba Amanda lives inside a rectangular grid of square pixels. Her body occupies some of these pixels. Other pixels may be either free or blocked. Amanda moves across the grid using the so-called amoeboid movement. In each step of such a movement, her body first shrinks by one pixel (one pixel of the body is removed and becomes free), and then grows at a different place (one previously-free pixel is added to the body). To prevent structural damage, Amanda's body always occupies a connected region of pixels, which means that any pair of pixels forming the body can be connected by a sequence of adjacent pixels without ever leaving the body. Two pixels are considered adjacent if they share a common side (each pixel has at most 4 neighbours). The body remains connected even during the movement, including the moment after removing a pixel and before adding another one. Your task is to help Amanda find her way around. Given her initial position and desired final position, suggest a sequence of valid moves leading from the former to the latter. The first line contains two integers r and c ( 1 <= r,c <= 50 ) -- the size of the rectangular grid in pixels. The next r lines contain c characters each, describing the initial position of Amanda. Each of those characters is either a dot texttt{.} denoting a free pixel, an asterisk texttt{*} denoting Amanda's body, or an texttt{X} denoting a blocked pixel which may never be occupied. The next line is empty. The next r lines describe the desired final position in the same format as the initial position. It is guaranteed that: Print texttt{YES} if it is possible for Amanda to go from the initial position to the final one. Otherwise, print texttt{NO} . If it is possible, on the next line print one integer m ( 0 <= m <= 10 ,000 ) -- the numbe"...