import sys
sys.setrecursionlimit(5*10**5)
input = sys.stdin.readline
from collections import defaultdict, deque, Counter
from heapq import heappop, heappush
from bisect import bisect_left, bisect_right
from math import gcd

h,w = map(int,input().split())
s = [input().rstrip() for i in range(h)]

g = [[0]*(w-2) for i in range(h-2)]

for i in range(1,h-1):
    for j in range(1, w-1):
        ok = 1
        for dx in [0,-1,1]:
            for dy in [0,-1,1]:
                ok &= s[i+dx][j+dy] == "."
        g[i-1][j-1] = ok
    

dx = [0,0,1,-1]
dy = [1,-1,0,0]
def bfs(x,y,g):
    que = deque([(x,y)])
    depth = [[-1]*(w-2) for i in range(h-2)]
    depth[x][y] = 0
    while que:
        x,y = que.popleft()
        for i in range(4):
            nx, ny = x+dx[i], y+dy[i]
            if not (0<= nx < h-2 and 0<=ny<w-2): continue
            if not g[nx][ny]: continue
            if depth[nx][ny] == -1:
                depth[nx][ny] = depth[x][y]+1
                que.append((nx,ny))
    return depth

d = bfs(0,0,g)
if d[-1][-1] == -1:
    print(0)
else:
    gg = [g[i][::1] for i in range(h-2)]
    gg[0][1] = 0
    if bfs(0,0,gg)[-1][-1] == -1:
        print(1)
        exit()
    gg = [g[i][::1] for i in range(h-2)]
    gg[1][0] = 0
    if bfs(0,0,gg)[-1][-1] == -1:
        print(1)
        exit()
    print(2)