using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Numerics;
using System.Text;
using static System.Console;
using static System.Convert;
using static System.Math;
using static Extentions;

class IO
{
    int idx;
    string[] input;

    public IO(TextReader reader)
    {
        input = reader.ReadToEnd().Split(new[] { " ", Environment.NewLine },
            StringSplitOptions.RemoveEmptyEntries);
    }

    T Get<T>(Func<string, T> parser) => parser(input[idx++]);

    public string S => Get(s => s);
    public char C => Get(char.Parse);
    public int I => Get(int.Parse);
    public long L => Get(long.Parse);
    public double F => Get(double.Parse);
    public decimal D => Get(decimal.Parse);
    public BigInteger B => Get(BigInteger.Parse);

    T[] Gets<T>(int n, Func<string, T> parser)
        => input.Skip((idx += n) - n).Take(n).Select(parser).ToArray();

    public string[] Ss(int n) => Gets(n, s => s);
    public char[] Cs(int n) => Gets(n, char.Parse);
    public int[] Is(int n) => Gets(n, int.Parse);
    public long[] Ls(int n) => Gets(n, long.Parse);
    public double[] Fs(int n) => Gets(n, double.Parse);
    public decimal[] Ds(int n) => Gets(n, decimal.Parse);
    public BigInteger[] Bs(int n) => Gets(n, BigInteger.Parse);

    public void Write<T>(params T[] xs) => WriteLine(string.Join(" ", xs));
    public void Write(params object[] xs) => WriteLine(string.Join(" ", xs));
}

class UnionFind
{
    int[] tree;
    bool[] check;

    public IEnumerable<int> Groups => tree
        .Select((x, i) => new Pair<int, int>(x, i))
        .Where(x => x.First < 0 && check[x.Second])
        .Select(x => x.Second);

    public UnionFind(int length)
    {
        tree = Enumerable.Repeat(-1, length).ToArray();
        check = new bool[length];
    }

    public bool Union(int x, int y)
    {
        this.Touch(x);
        this.Touch(y);
        x = this.Find(x);
        y = this.Find(y);
        if (x == y) return false;
        if (tree[x] > tree[y]) Swap(ref x, ref y);
        tree[x] += tree[y];
        tree[y] = x;
        return true;
    }

    public int Find(int x)
    {
        if (tree[x] < 0) return x;
        return tree[x] = this.Find(tree[x]);
    }

    public bool IsSameGroup(int x, int y) => this.Find(x) == this.Find(y);

    public IEnumerable<int> GetElements(int x) => tree
        .Select((_, i) => i)
        .Where(y => Find(y) == x);

    public void Touch(int x) => check[x] = true;
}

struct Pair<T1, T2>
{
    public T1 First { get; set; }
    public T2 Second { get; set; }

    public Pair(T1 first, T2 second)
    {
        this.First = first;
        this.Second = second;
    }
}

static class Extentions
{
    public static void ForEach<T>(this IEnumerable<T> seq, Action<T, int> act)
    {
        for (var i = 0; i < seq.Count(); i++) act(seq.ElementAt(i), i);
    }

    public static void Swap<T>(ref T x, ref T y)
    {
        var tmp = x;
        x = y;
        y = tmp;
    }
}

static class Program
{
    public static void Main()
    {
#if !DEBUG
        SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false });
#endif
        Solve(new IO(In));
        Out.Flush();
    }

    static void Solve(IO io)
    {
        var w = io.I;
        var h = io.I;
        var c = new bool[h, w];

        var uf = new UnionFind(Encode(h, w));

        for (var i = 0; i < h; i++)
            io.S.ForEach((x, j) =>
                { if (c[i, j] = x == '.') uf.Touch(Encode(i, j)); });

        for (var i = 0; i < h; i++)
            for (var j = 0; j < w - 1; j++)
                if (c[i, j] && c[i, j + 1])
                    uf.Union(Encode(i, j), Encode(i, j + 1));

        for (var j = 0; j < w; j++)
            for (var i = 0; i < h - 1; i++)
                if (c[i, j] && c[i + 1, j])
                    uf.Union(Encode(i, j), Encode(i + 1, j));

        var ans = int.MaxValue;

        foreach (var p1 in uf.GetElements(uf.Groups.First()))
            foreach (var p2 in uf.GetElements(uf.Groups.Last()))
                if (p1 != p2) ans = Min(ans, Distance(p1, p2) - 1);

        io.Write(ans);
    }

    static int Encode(int x, int y) => x * 100 + y;

    static int Distance(int p1, int p2)
    {
        var x1 = p1 / 100;
        var y1 = p1 % 100;
        var x2 = p2 / 100;
        var y2 = p2 % 100;

        return Abs(x1 - x2) + Abs(y1 - y2);
    }
}