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
    

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 dx in [1,0,-1]:
            for dy in [1,0,-1]:
                if dx == 0 and dy == 0: continue
                nx, ny = x+dx, y+dy
                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:
    for i in range(h-2):
        for j in range(w-2):
            d1 = max(i,j)
            d2 = max(h-3-i, w-3-j)
            if d1 <= 1 or d2 <= 1: continue
            gg = [g[i][::1] for i in range(h-2)]
            for di in [-1,0,1]:
                for dj in [-1,0,1]:
                    gg[i+di][j+dj] = 0
            if bfs(0,0,gg)[-1][-1] == -1:
                print(1)
                exit()
    print(2)