using System;
using System.Collections.Generic;

class program
{
    public static void Main()
    {
        var str = Console.ReadLine().Split(' ');
        var W = int.Parse(str[0]);
        var H = int.Parse(str[1]);

        var room = new String[H, W];

        for (int i = 0; i < H; i++)
        {
            var buf = Console.ReadLine();
            for (int j = 0; j < W; j++)
            {
                room[i, j] = buf.ToCharArray()[j].ToString();
            }
        }

        var room1 = new bool[H, W];
        var flag = false;
        for (int i = 0; i < H; i++)
        {
            for (int j = 0; j < W; j++)
            {
                if (room[i, j] == ".")
                {
                    room1[i, j] = true;
                    check(room, room1, j, i);
                    flag = true;
                    break;
                }
            }
            if (flag) break;
        }

        var room2 = new bool[H, W];
        flag = false;
        for (int i = 0; i < H; i++)
        {
            for (int j = 0; j < W; j++)
            {
                if (room[i, j] == "." && !room1[i, j])
                {
                    room2[i, j] = true;
                    check(room, room2, j, i);
                    flag = true;
                    break;
                }
            }
            if (flag) break;
        }

        int minWight = 1000;
        for (int i = 0; i < H; i++)
        {
            for (int j = 0; j < W; j++)
            {
                var point1 = room1[i, j];
                for (int k = 0; k < H; k++)
                {
                    for (int l = 0; l < W; l++)
                    {
                        if (point1 && room2[k, l])
                        {
                            var man = System.Math.Abs(i - k) + System.Math.Abs(j - l);
                            man--;
                            minWight = minWight > man ? man : minWight;
                        }
                    }
                }
            }
        }

        Console.WriteLine(minWight);
    }

    public static void check(String[,] roombase, bool[,] room, int X, int Y)
    {
        if (roombase[Y, X + 1] == ".")
        {
            if (!room[Y, X + 1])
            {
                room[Y, X + 1] = true;
                check(roombase, room, X + 1, Y);
            }
        }

        if (roombase[Y - 1, X] == ".")
        {
            if (!room[Y - 1, X])
            {
                room[Y - 1, X] = true;
                check(roombase, room, X, Y - 1);
            }

        }

        if (roombase[Y, X - 1] == ".")
        {
            if (!room[Y, X - 1])
            {
                room[Y, X - 1] = true;
                check(roombase, room, X - 1, Y);
            }
        }

        if (roombase[Y + 1, X] == ".")
        {
            if (!room[Y + 1, X])
            {
                room[Y + 1, X] = true;
                check(roombase, room, X, Y + 1);
            }
        }
    }
}