using System;
using System.Linq;
using System.Collections.Generic;

class Program
{    
    static void Main()
    {
        int w, h;
        mul(out w, out h);
        var c = new char[w, h];
        for(int i=0;i< h; i++)
        {
            var s = rs();
            for (int j = 0; j < w; j++)
                c[j, i] = s[j];
        }

        int num = 1;
        var hole = new int[w, h];
        Action<int, int> dfs = null;
        dfs = (a, b) =>
        {
            c[b, a] = '#';
            hole[b, a] = num;
            int[] dx = { 0, 0, 1, -1 }, dy = { 1, -1, 0, 0 };
            for(int i = 0; i < 4; i++)
            {
                int nx = a + dx[i], ny = b + dy[i];
                if (c[ny, nx] == '.')
                {
                    hole[ny, nx] = num;
                    dfs(nx, ny);
                }
            }
        };
     
        for(int i=0;i< h; i++)
        {
            for(int j=0;j< w; j++)
            {
                if (c[j, i] == '.')
                {
                    dfs(i, j);
                    num++;
                }
            }
        }

        int ans = int.MaxValue;

        for(int i = 0; i < h; i++)
            for(int j=0;j< w; j++)
                for (int k = 0; k < h; k++)
                    for(int l=0;l< w; l++)
                        if (hole[j, i] == 1 && hole[l, k] == 2)
                            ans = Math.Min(ans, Math.Abs(i - k) + Math.Abs(j - l) - 1);

        Console.WriteLine(ans);
    }
    #region Scan
    static int ri() { return int.Parse(Console.ReadLine().Trim()); }
    static long rl() { return long.Parse(Console.ReadLine().Trim()); }
    static double rd() { return double.Parse(Console.ReadLine().Trim()); }
    static string rs() { return Console.ReadLine().Trim(); }
    static int[] ria() { return Console.ReadLine().Trim().Split().Select(int.Parse).ToArray(); }
    static long[] rla() { return Console.ReadLine().Trim().Split().Select(long.Parse).ToArray(); }
    static double[] rda() { return Console.ReadLine().Trim().Split().Select(double.Parse).ToArray(); }
    static string[] rsa() { return Console.ReadLine().Trim().Split(); }
    static void mul(out int a, out int b) { var arr = ria(); a = arr[0]; b = arr[1]; }
    static void mul(out int a, out int b, out int c) { var arr = ria(); a = arr[0]; b = arr[1]; c = arr[2]; }
    static void mul(out int a, out int b, out int c, out int d) { var arr = ria(); a = arr[0]; b = arr[1]; c = arr[2]; d = arr[3]; }
    static void mul(out long a, out long b) { var arr = rla(); a = arr[0]; b = arr[1]; }
    static void mul(out long a, out long b, out long c) { var arr = rla(); a = arr[0]; b = arr[1]; c = arr[2]; }
    static void mul(out long a, out long b, out long c, out long d) { var arr = rla(); a = arr[0]; b = arr[1]; c = arr[2]; d = arr[3]; }
    #endregion
    #region Math
    const int mod = 1000000007;
    static bool isprime(long n){ if (n < 2) return false; for (long i = 2; i * i <= n; i++) if (n % i == 0) return false; return true; }
    static long gcd(long a, long b) { return a == 0 ? b : gcd(b % a, a); }
    static long lcm(long a, long b) { return a * b / gcd(a, b); }
    #endregion
}