import math._
import scala.util.control.Breaks._
import scala.collection.mutable.Queue

object Main {
  def display(tab: Array[Array[Boolean]]) {
    for (xs <- tab) {
      for (j <- 0 to xs.length-1) {
        if (xs(j)) print("o")
        else print("x")
      }
      println()
    }
  }

  def calc(rows: Int, cols: Int, g: Array[Array[Char]]): Int = {
    var tab = Array.fill(rows, cols)(false)

    val pos = (for (i <- 0 to rows-1; j <- 0 to cols-1 if g(i)(j) == '.')
                 yield (i, j)).head

    var q = new Queue[(Int, Int)]
    q.enqueue((pos._1, pos._2))
    while (!q.isEmpty) {
      val (r, c) = q.dequeue

      if (g(r)(c) == '.' && !tab(r)(c)) {
        tab(r)(c) = true
        for ((dr, dc) <- Array((-1, 0), (1, 0), (0, -1), (0, 1))) {
          val row = r + dr
          val col = c + dc
          if (0 <= row && row < rows && 0 <= col && col < cols) {
            if (g(row)(col) == '.') {
              q.enqueue((row, col))
            }
          }
        }
      }
    }

    var ans = Integer.MAX_VALUE
    for (i <- 0 to rows-1; j <- 0 to cols-1) {
      if (tab(i)(j)) {
        for (k <- 0 to rows-1; m <- 0 to cols-1) {
          if (g(k)(m) == '.' && !tab(k)(m)) {
            ans = min(ans, abs(i - k) + abs(j - m) - 1)
          }
        }
      }
    }
    ans
  }

  def main(args: Array[String]) {
    val sc = new java.util.Scanner(System.in)
    val W, H = sc.nextInt

    val g = Array.fill(H, W)(' ')
    for (i <- 0 to H-1) {
      val s = sc.next
      for (j <- 0 to W-1) {
        g(i)(j) = s(j)
      }
    }
    println(calc(H, W, g))
  }
}