def g;gets.split.map(&:to_i)end
w,h=g
c=(0...h).map{gets+?+}+[?+*w]
fx=fy=0
fy=(0...h).find{|i|fx=(0...w).find{|j|c[i][j]==?.}}
q=[[fx,fy,0]]
c[fy][fx]=?+
n=0
while q[n]
  x,y=q[n]
  [[x+1,y],[x-1,y],[x,y+1],[x,y-1]].each{|tx,ty|
    if c[ty][tx]==?.
      q<<[tx,ty,0]
      c[ty][tx]=?+
    end
  }
  n+=1
end
while q[0]
  x,y,i=q.shift
  [[x+1,y],[x-1,y],[x,y+1],[x,y-1]].each{|tx,ty|
    case c[ty][tx]
    when ?.
      p i
      exit
    when ?#
      q<<[tx,ty,i+1]
      c[ty][tx]=?+
    end
  }
end