import java.util.*;

public class Main {
	public static void main (String[] args) {
    	Scanner sc = new Scanner(System.in);
    	int w = sc.nextInt();
    	int h = sc.nextInt();
    	char[][] field = new char[h][];
    	for (int i = 0; i < h; i++) {
    	    field[i] = sc.next().toCharArray();
    	}
    	HashSet<Integer> lefts = new HashSet<>();
    	HashSet<Integer> rights = new HashSet<>();
    	boolean used = false;
    	for (int i = 0; i < h; i++) {
    	    for (int j = 0; j < w; j++) {
    	        if (field[i][j] == '.') {
    	            HashSet<Integer> tmp;
    	            if (used) {
    	                tmp = rights;
    	            } else {
    	                tmp = lefts;
    	                used = true;
    	            }
    	            PriorityQueue<Integer> queue = new PriorityQueue<>();
    	            queue.add(i * w + j);
    	            while (queue.size() > 0) {
    	                int x = queue.poll();
    	                if (field[x / w][x % w] == '#') {
    	                    continue;
    	                }
    	                field[x / w][x % w] = '#';
    	                queue.add(x + 1);
    	                queue.add(x - 1);
    	                queue.add(x + w);
    	                queue.add(x - w);
    	                tmp.add(x);
    	            }
    	        }
    	    }
    	}
    	int min = Integer.MAX_VALUE;
    	for (int x : lefts) {
    	    for (int y : rights) {
    	        min = Math.min(min, getDist(x, y, w));
    	    }
    	}
    	System.out.println(min);
	}
	
	static int getDist(int x, int y, int width) {
	    return Math.abs(x / width - y / width) + Math.abs(x % width - y % width) - 1;
	}
}