import strutils, sequtils, algorithm, math


var
  wh = split(readLine(stdin), ' ').map(parseInt)
  count = 0
  board = newSeq[seq[int]](wh[1])
  dire = [[0, -1], [1, 0], [0, 1], [-1, 0]]
  pre = 0

proc bfs(x, y, count: int): int =
  var min_dis = high(int)
  if count == 0:
    for i in countup(1, wh[1] - 2):
      for j in countup(1, wh[0] - 2):
        if board[i][j] == 1:
          for d in dire:
            if 0 < j + d[0] and j + d[0] < wh[0] - 1 and 0 < i + d[1] and i + d[1] < wh[1] - 1:
              if board[i+d[1]][j+d[0]] == -1:
                min_dis = min(bfs(j + d[0], i + d[1], count + 1), min_dis)
    return min_dis
  else:
    board[y][x] = -2
    for d in dire:
      if 0 < x + d[0] and x + d[0] < wh[0] - 1 and 0 < y + d[1] and y + d[1] < wh[1] - 1:
        if board[y+d[1]][x+d[0]] == 2:
          board[y][x] = -1
          return count
    for d in dire:
      if 0 < x + d[0] and x + d[0] < wh[0] - 1 and 0 < y + d[1] and y + d[1] < wh[1] - 1:
        if board[y+d[1]][x+d[0]] == -1:
          min_dis = min(bfs(x + d[0], y + d[1], count + 1), min_dis)
    board[y][x] = -1
    return min_dis




proc init(pre: var int; x, y: int) =
  if pre == 0:
    for i in countup(1, wh[1] - 2):
      for j in countup(1, wh[0] - 2):
        if board[i][j] == 0:
          pre += 1
          board[i][j] = pre
          for d in dire:
            init(pre, j + d[0], i + d[1])
  else:
    if board[y][x] == 0:
      board[y][x] = pre
      for d in dire:
        if 0 < x + d[0] and x + d[0] < wh[0] - 1 and 0 < y + d[1] and y + d[1] < wh[1] - 1:
          init(pre, x + d[0], y + d[1])

for i in countup(0, wh[1] - 1):
  var line = readLine(stdin)
  var row = newSeq[char](0)
  for c in line:
    row.add(c)
  board[i] = row.map(proc (x: char): int =
                       result = if x == '#': -1 else: 0
                       return)

init(pre, 1, 1)
echo(bfs(0, 0, 0))