using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
using System.Runtime.Intrinsics.Arm;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static string[] SList(long n) => Enumerable.Repeat(0, (int)n).Select(_ => ReadLine()).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (h, w) = (c[0], c[1]);
        var s = SList(h);
        var lh = h * 2 - 1;
        var lw = w * 2 - 1;
        var len = new int[lh, lw];
        var INF = int.MaxValue / 2;
        for (var i = 0; i < lh; ++i) for (var j = 0; j < lw; ++j) len[i, j] = INF;
        len[0, 0] = 0;
        var q = new Queue<(int x, int y)>();
        q.Enqueue((0, 0));
        var mx = new int[] { -1, 1, 0, 0 };
        var my = new int[] { 0, 0, -1, 1 };
        while (q.Count > 0)
        {
            var cur = q.Dequeue();
            for (var i = 0; i < 4; ++i)
            {
                var nx = cur.x + mx[i];
                var ny = cur.y + my[i];
                if (nx < 0 || nx >= lh || ny < 0 || ny >= lw) continue;
                if (len[nx, ny] <= len[cur.x, cur.y] + 1) continue;
                if (nx % 2 == 0 && ny % 2 == 0 && s[nx / 2][ny / 2] == '#') continue;
                len[nx, ny] = len[cur.x, cur.y] + 1;
                q.Enqueue((nx, ny));
            }
            if (cur.x % 2 == 0)
            {
                var nx = cur.x - 2;
                if (0 <= nx && len[nx, cur.y] > len[cur.x, cur.y] + 1 && (cur.y % 2 == 1 || s[nx / 2][cur.y / 2] != '#'))
                {
                    len[nx, cur.y] = len[cur.x, cur.y] + 1;
                    q.Enqueue((nx, cur.y));
                }
                nx = cur.x + 2;
                if (nx < lh && len[nx, cur.y] > len[cur.x, cur.y] + 1 && (cur.y % 2 == 1 || s[nx / 2][cur.y / 2] != '#'))
                {
                    len[nx, cur.y] = len[cur.x, cur.y] + 1;
                    q.Enqueue((nx, cur.y));
                }
            }
            if (cur.y % 2 == 0)
            {
                var ny = cur.y - 2;
                if (0 <= ny && len[cur.x, ny] > len[cur.x, cur.y] + 1 && (cur.x % 2 == 1 || s[cur.x / 2][ny / 2] != '#'))
                {
                    len[cur.x, ny] = len[cur.x, cur.y] + 1;
                    q.Enqueue((cur.x, ny));
                }
                ny = cur.y + 2;
                if (ny < lw && len[cur.x, ny] > len[cur.x, cur.y] + 1 && (cur.x % 2 == 1 || s[cur.x / 2][ny / 2] != '#'))
                {
                    len[cur.x, ny] = len[cur.x, cur.y] + 1;
                    q.Enqueue((cur.x, ny));
                }
            }
        }
        WriteLine(len[lh - 1, lw - 1]);
    }
}