from collections import deque
w,h =map(int,input().split())
grid=[input() for i in range(h)]
dist=[[0]*w for i in range(h)]
l=[1,0,-1,0]
r=[0,1,0,-1]

def  bfs(x,dq):
    while dq:
        ll,rr=dq.popleft()
        for i in range(4):
            t1 = ll+l[i]
            t2 = rr+r[i]
            if 0 <= t1 < h and 0 <= t2 < w:
                if grid[t1][t2] == '.':
                    if dist[t1][t2] == 0:
                        dist[t1][t2] = x
                        dq.append([t1,t2])
                        
            
def s(x):
    for i in range(h):
        for j in range(w):
            if grid[i][j] == '.':
                if dist[i][j] == 0:
                    de=deque()
                    de.append([i,j])
                    dist[i][j]=x
                    bfs(x,de)
                    return [i,j]
          
one=s(1)
s(2)

cost=[[1000]*w for i in range(h)]
cost[one[0]][one[1]] = 0
            
def  bfs2(x):
    ans = 1000
    de = deque()
    de.append(x)
    while de:
        ll,rr = de.popleft()
        for i in range(4):
            t1 = ll+l[i]
            t2 = rr+r[i]
            if 0 <= t1 < h and 0 <= t2 < w:
                if dist[t1][t2] == 1:
                    if cost[t1][t2] > cost[ll][rr]:
                        de.append([t1,t2])
                        cost[t1][t2] = cost[ll][rr]
                elif dist[t1][t2] == 0:
                    if cost[t1][t2] > cost[ll][rr]+1:
                        cost[t1][t2] = cost[ll][rr]+1
                        de.append([t1,t2])
                        
                elif  dist[t1][t2] == 2:
                    ans = min(ans,cost[ll][rr])
    return ans
                    
print(bfs2(one))