import java.io.*;
import java.util.*;
public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String wh[] = br.readLine().split(" ");
		int w = Integer.parseInt(wh[0]);
		int h = Integer.parseInt(wh[1]);
		int space[][] = new int[w][h];
		boolean first = true;
		for (int i = 0; i < h; i++) {
			String line[] = br.readLine().split("");
			for (int k = 0; k < w; k++) {
				if (line[k].equals("#")) {
					space[k][i] = 0;
				} else {
					if (first) {
						space[k][i] = 1;
						first = false;
					} else {
						space[k][i] = 2;
					}
				}
			}
		}
		int xy[] = {1, 0, -1, 0, 1};
		while (true) {
			boolean all = true;
			for (int i = 1; i < h-1; i++) {
				for (int k = 1; k < w-1; k++) {
					if (space[k][i] == 2) {
						for (int l = 0; l < xy.length - 1; l++) {
							if (space[k+xy[l]][i+xy[l+1]] == 1) {
								space[k][i] = 1;
								all = false;
							}
						}
					}
				}
			}
			if (all) {
				break;
			}
		}
		int dis = w + h;
		for (int i = 1; i < h-1; i++) {
			for (int k = 1; k < w-1; k++) {
				if (space[k][i] == 1) {
					for (int p = 1; p < h-1; p++) {
						for (int q = 1; q < w-1; q++) {
							if (space[q][p] == 2) {
								int tance = Math.abs(i-p)+Math.abs(k-q)-1;
								if (tance < dis) {
									dis = tance;
								}
							}
						}
					}
				}
			}
		}
		System.out.println(dis);
	}
}