Shared code

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.LinkedList;
import java.util.Queue;
import java.util.StringTokenizer;

public class monsters {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int n = scn.nextInt();
		int m = scn.nextInt();
		char[][] arr = new char[n][m];
		for (int i = 0; i < n; ++i) {
			arr[i] = scn.next().toCharArray();
		}
		solve(n, m, arr);
	}

	public static void solve(int n, int m, char[][] arr) {
		Queue<Point> q = new LinkedList<>();
		int[][] aux = new int[n][m];
		Point start = null;
		for (int i = 0; i < n; ++i) {
			for (int j = 0; j < m; ++j) {
				char c = arr[i][j];
				if (c == 'M') {
					q.add(new Point(i, j, 0));
				} else {
					aux[i][j] = Integer.MAX_VALUE;
				}

				if (c == 'A') {
					start = new Point(i, j, 0);
				}
			}
		}

		while (q.size() > 0) {
			Point p = q.remove();
			int x = p.x;
			int y = p.y;
			int d = p.d;

			aux[x][y] = d;

			for (int i = 0; i < 4; ++i) {
				int nx = x + dx[i];
				int ny = y + dy[i];

				if (check(n, m, nx, ny) && d + 1 <= aux[nx][ny] && arr[nx][ny] != '#') {
					q.add(new Point(nx, ny, d + 1));
				}
			}
		}
		boolean found = false;
		q.add(start);
		start.path = "";
		boolean[][] visited = new boolean[n][m];
		while (q.size() > 0) {
			Point p = q.remove();
			int x = p.x;
			int y = p.y;
			int d = p.d;
			visited[x][y] = true;

			if (end(n, m, x, y)) {
				found = true;
				out.println("YES");
				out.println(p.path.length());
				out.println(p.path);
				break;
			}

			for (int i = 0; i < 4; ++i) {
				int nx = x + dx[i];
				int ny = y + dy[i];

				if (check(n, m, nx, ny) && !visited[nx][ny] && d + 1 < aux[nx][ny] && arr[nx][ny] != '#') {
					Point np = new Point(nx, ny, d + 1);
					np.path = p.path + dir[i];
					q.add(np);
				}
			}
		}
		if (!found) {
			out.println("NO");
		}
		out.flush();
	}

	public static boolean check(int n, int m, int i, int j) {
		if (i >= 0 && i < n && j >= 0 && j < m) {
			return true;
		}
		return false;
	}

	static int[] dx = { 1, -1, 0, 0 };
	static int[] dy = { 0, 0, 1, -1 };
	static char[] dir = { 'D', 'U', 'R', 'L' };

	public static boolean end(int n, int m, int i, int j) {
		if (i == n - 1 || i == 0 || j == 0 || j == m - 1) {
			return true;
		}

		return false;
	}

	public static class Point {
		int x;
		int y;
		int d;
		String path;

		Point(int x, int y, int d) {
			this.x = x;
			this.y = y;
			this.d = d;
		}
	}

	static FastScanner scn = new FastScanner();
	static PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));

	static class FastScanner {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer("");

		String next() {
			while (!st.hasMoreTokens())
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		int[] readArray(int n) {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = nextInt();
			return a;
		}

		long nextLong() {
			return Long.parseLong(next());
		}
	}

}