"""
H 問題おもしろい

if : 最短経路でない -> 関係ない
ということで最短経路があるかどうかのみかんがえる
"""

from math import isqrt
from collections import deque
import sys

mod = 998244353
input = sys.stdin.readline
II = lambda : int(input())
MI = lambda : (int(_) for _ in input().split())
LI = lambda : list(int(_) for _ in input().split())
SI = lambda : input()

h, w = MI()
c = [SI() for i in range(h)]

ok = [[2] * w for i in range(h)]
ok[0][0] = 0
hs = [w] * h
ws = [h] * w
for i in range(h):
    for j in range(w):
        if c[i][j] == "#": continue
        if i != 0:
            ok[i][j] = min(ok[i][j], ok[i-1][j])
            if hs[i-1] <= j:
                ok[i][j] = min(ok[i][j], 1)
        if j != 0:
            ok[i][j] = min(ok[i][j], ok[i][j-1])
            if ws[j-1] <= i:
                ok[i][j] = min(ok[i][j], 1)
        if ok[i][j] == 0:
            hs[i] = min(hs[i], j)
            ws[j] = min(ws[j], i)

print(h + w - 2 + ok[-1][-1])