from collections import *

def dfs(ux, uy):
    for k in range(4):
        x, y = ux + dx[k], uy + dy[k]
        if x < 0 or x > H - 1 or y < 0 or y > W - 1:
            continue
        if C[x][y] == "#":
            continue
        if (x, y) in S:
            continue
        S.add((x, y))
        dfs(x, y)
    return 
        

W, H = map(int, input().split())
C = []
for i in range(H):
    C.append(list(input()))
dx = [1, 0, -1, 0]
dy = [0, 1, 0, -1]
S = set()
flag = 1
for i in range(H):
    for j in range(W):
        if C[i][j] == "#":
            continue
        if (i, j) in S:
            continue
        if flag:
            sx, sy = i, j
            S.add((i, j))
            dfs(i, j)
            flag = 0
        else:
            gx, gy = i, j
            break
        
Q = deque()
Q.append((sx, sy))
inf = 10 ** 18
dist = [[inf] * W for i in range(H)]
dist[sx][sy] = 0
while Q:
    ux, uy = Q.popleft()
    for k in range(4):
        x, y = ux + dx[k], uy + dy[k]
        if x < 0 or x > H - 1 or y < 0 or y > W - 1:
            continue
        if C[x][y] == "#":
            if dist[x][y] > dist[ux][uy] + 1:
                dist[x][y] = dist[ux][uy] + 1
                Q.append((x,y))
        else:
            if dist[x][y] > dist[ux][uy]:
                dist[x][y] = dist[ux][uy]
                Q.appendleft((x,y))
print(dist[gx][gy])