h,w = map(int,input().split())
s = [input()+"#" for _ in range(h)]+["#"*(w+1)]
def check(t):
    f = [[False]*w for _ in range(h)]; f[1][1] = True; st = [(1,1)]
    while st:
        px,py = st.pop()
        for dx in range(-1,2):
            for dy in range(-1,2):
                nx,ny = px+dx,py+dy; g = True
                if f[nx][ny]: continue
                for i in range(-1,2):
                    for j in range(-1,2):
                        g &= t[nx+i][ny+j]=="."
                if g: f[nx][ny] = True; st.append((nx,ny))
    return f[h-2][w-2]
if not check(s): exit(print(0))
for i in range(h):
    for j in range(w):
        if 0<=i<=2 and 0<=j<=2 or h-3<=i<=h-1 and w-3<=j<=w-1: continue
        t = [list(si) for si in s]; t[i][j] = "#"
        if not check(t): exit(print(1))
print(2)