using System;
using System.Diagnostics;
using System.Collections.Generic;
using System.Linq;
using Enu = System.Linq.Enumerable;

class Solution {
    int[] dx = new int[] { 1, 0, -1, 0 }, dy = new int[] { 0, 1, 0, -1 };
    int W, H;
    int[,] field;
    bool[,] visited;
    Queue<point>[] hole;
    void calc() {
        rio(out W, out H);

        field = new int[H, W];
        for (int i = 0; i < H; i++) {
            var s = Console.ReadLine();
            for (int j = 0; j < W; j++) {
                field[i, j] = s[j] == '.' ? 0 : 1;
            }
        }

        visited = new bool[H, W];
        hole = new Queue<point>[2];
        for (int i = 0; i < 2; i++) hole[i] = new Queue<point>();

        dfs(0);
        dfs(1);

        var dijkstra = new Algorithm.Dijkstra(H * W);
        for (int i = 0; i < H; i++) {
            for (int j = 0; j < W; j++) {
                for (int k = 0; k < 4; k++) {
                    int ni = i + dy[k], nj = j + dx[k];
                    if (ni < 0 || H <= ni || nj < 0 || W <= nj) continue;
                    dijkstra.addDirEdge(i * W + j, ni * W + nj, field[ni, nj]);
                }
            }
        }

        var start = hole[0].First();
        dijkstra.calcShortestPath(start.y * W + start.x);

        var goal = hole[1].First();
        var ans = dijkstra.d[goal.y * W + goal.x];
        Console.WriteLine(ans);
    }

    void dfs(int n) {
        for (int i = 0; i < H; i++) {
            for (int j = 0; j < W; j++) {
                if (field[i, j] == 1 || visited[i, j]) continue;

                var search = new Queue<point>();
                search.Enqueue(new point(j, i));

                while (search.Count != 0) {
                    var p = search.Dequeue();
                    visited[p.y, p.x] = true;
                    hole[n].Enqueue(new point(p.x, p.y));

                    for (int k = 0; k < dx.Length; k++) {
                        var np = new point(p.x + dx[k], p.y + dy[k]);
                        if (np.x < 0 || W <= np.x || np.y < 0 || H <= np.y) continue;
                        if (field[np.y, np.x] == 0 && !visited[np.y, np.x])
                            search.Enqueue(np);
                    }
                }
                return;
            }
        }
        return;
    }



    static void Main(string[] args) {
        new Solution().calc();
    }

    #region
    static int ri() { return int.Parse(Console.ReadLine()); }
    static int[] ria(int n) {
        if (n <= 0) { Console.ReadLine(); return new int[0]; }
        else return Console.ReadLine().Trim().Split(' ').Select(int.Parse).ToArray();
    }
    static void rio(out int p1) { p1 = ri(); }
    static void rio(out int p1, out int p2) { var r = ria(2); p1 = r[0]; p2 = r[1]; }
    static void rio(out int p1, out int p2, out int p3) { var r = ria(3); p1 = r[0]; p2 = r[1]; p3 = r[2]; }
    static void rio(out int p1, out int p2, out int p3, out int p4) { var r = ria(4); p1 = r[0]; p2 = r[1]; p3 = r[2]; p4 = r[3]; }
    static void rio(out int p1, out int p2, out int p3, out int p4, out int p5) { var r = ria(5); p1 = r[0]; p2 = r[1]; p3 = r[2]; p4 = r[3]; p5 = r[4]; }
    static long rl() { return long.Parse(Console.ReadLine()); }
    static long[] rla(int n) {
        if (n <= 0) { Console.ReadLine(); return new long[0]; }
        else return Console.ReadLine().Trim().Split(' ').Select(long.Parse).ToArray();
    }
    static void rlo(out long p1) { p1 = rl(); }
    static void rlo(out long p1, out long p2) { var r = rla(2); p1 = r[0]; p2 = r[1]; }
    static void rlo(out long p1, out long p2, out long p3) { var r = rla(3); p1 = r[0]; p2 = r[1]; p3 = r[2]; }
    static void rlo(out long p1, out long p2, out long p3, out long p4) { var r = rla(4); p1 = r[0]; p2 = r[1]; p3 = r[2]; p4 = r[3]; }
    static void rlo(out long p1, out long p2, out long p3, out long p4, out long p5) { var r = rla(5); p1 = r[0]; p2 = r[1]; p3 = r[2]; p4 = r[3]; p5 = r[4]; }
    static double rd() { return double.Parse(Console.ReadLine()); }
    static double[] rda(int n) {
        if (n <= 0) { Console.ReadLine(); return new double[0]; }
        else return Console.ReadLine().Trim().Split(' ').Select(double.Parse).ToArray();
    }
    static void rdo(out double p1) { p1 = rd(); }
    static void rdo(out double p1, out double p2) { var r = rda(2); p1 = r[0]; p2 = r[1]; }
    static void rdo(out double p1, out double p2, out double p3) { var r = rda(3); p1 = r[0]; p2 = r[1]; p3 = r[2]; }
    static void rdo(out double p1, out double p2, out double p3, out double p4) { var r = rda(4); p1 = r[0]; p2 = r[1]; p3 = r[2]; p4 = r[3]; }
    static void rdo(out double p1, out double p2, out double p3, out double p4, out double p5) { var r = rda(5); p1 = r[0]; p2 = r[1]; p3 = r[2]; p4 = r[3]; p5 = r[4]; }
    static void swap<T>(ref T x, ref T y) { T temp = x; x = y; y = temp; }
    static void wa1<T>(T[] a) { Debug.WriteLine(string.Join(" ", a)); }
    static void wa2<T>(T[][] a) {
        foreach (var row in a) {
            Debug.WriteLine(String.Join(" ", row));
        }
    }
    [DebuggerDisplay("{x} , {y}")]
    class point {
        public int x, y;
        public point(int x, int y) {
            this.x = x; this.y = y;
        }
    }
    #endregion
}

static class Extention {
    public static T[][] ToJagArray<T>(this T[,] a) {
        int n = a.GetLength(0), m = a.GetLength(1);
        var ret = new T[n][];
        for (int i = 0; i < n; i++) {
            ret[i] = new T[m];
            for (int j = 0; j < m; j++) {
                ret[i][j] = a[i, j];
            }
        }
        return ret;
    }
}

namespace Algorithm {
    using T = System.Int32;
    // require PriorityQueue
    public class Dijkstra {
        public T INF = (T)1e9;
        [DebuggerDisplay("from : {from}, to : {to}, cost : {cost}")]
        private class edge {
            public int from, to;
            public T cost;
            public edge(int from, int to, T cost) {
                this.from = from; this.to = to; this.cost = cost;
            }
        }
        [DebuggerDisplay("v : {v}, cost : {cost}")]
        private class state {
            public int v;
            public T cost;
            public state(int v, T cost) {
                this.v = v; this.cost = cost;
            }
        }
        private int vnum;
        private List<edge>[] edgelists;
        public T[] d;
        private PriorityQueue<state> que;

        public Dijkstra(int vnum) {
            this.vnum = vnum;
            edgelists = new List<edge>[vnum + 1];
            for (int i = 0; i < edgelists.Length; i++)
                edgelists[i] = new List<edge>();
            d = new T[vnum + 1];
        }
        public void addDirEdge(int v1, int v2, T cost) {
            edgelists[v1].Add(new edge(v1, v2, cost));
        }
        public void addUnDirEdge(int v1, int v2, T cost) {
            edgelists[v1].Add(new edge(v1, v2, cost));
            edgelists[v2].Add(new edge(v2, v1, cost));
        }
        public void calcShortestPath(int s) {
            for (int i = 0; i < d.Length; i++)
                d[i] = INF;
            que = new PriorityQueue<state>((s1, s2) => s2.cost.CompareTo(s1.cost));
            d[s] = 0;
            que.Push(new state(s, 0));

            while (que.Count() != 0) {
                var t = que.Pop();
                int v = t.v;
                if (d[v] < t.cost) continue;
                foreach (var e in edgelists[v]) {
                    if (d[e.to] > d[v] + e.cost) {
                        d[e.to] = d[v] + e.cost;
                        que.Push(new state(e.to, d[e.to]));
                    }
                }
            }
        }
    }

    public class PriorityQueue<T> {
        private List<T> buffer;
        private Comparison<T> comp;
        // 昇順
        // (e1, e2) => e2.CompareTo(e1)  
        // 降順
        // (e1, e2) => e1.CompareTo(e2)
        public PriorityQueue(Comparison<T> comp) {
            buffer = new List<T>();
            this.comp = comp;
        }
        public PriorityQueue(Comparison<T> comp, IEnumerable<T> data)
            : this(comp) {
            foreach (T e in data) Push(e);
        }

        public void Push(T elem) { PushHeap(this.buffer, elem); }
        public T Pop() { return PopHeap(this.buffer); }
        public int Count() { return buffer.Count; }

        public T Top() { return buffer[0]; }
        private void PushHeap(List<T> array, T elem) {
            int n = array.Count;
            array.Add(elem);

            while (n != 0) {
                int i = (n - 1) / 2;
                // 親と値を入れ替え
                if (comp(array[n], array[i]) > 0) {
                    T tmp = array[n]; array[n] = array[i]; array[i] = tmp;
                }
                n = i;
            }
        }

        private T PopHeap(List<T> array) {
            int n = array.Count - 1;
            T returnelem = array[0];
            array[0] = array[n];
            array.RemoveAt(n);

            for (int i = 0, j; (j = 2 * i + 1) < n; ) {
                // 値の大きい方の子を選ぶ
                if ((j != n - 1) && (comp(array[j], array[j + 1]) < 0))
                    j++;
                // 子と値を入れ替え
                if (comp(array[i], array[j]) < 0) {
                    T tmp = array[j]; array[j] = array[i]; array[i] = tmp;
                }
                i = j;
            }
            return returnelem;
        }
    }
}