from collections import deque
import sys

INF = 100000000

def bfs(si, sj, h, w, C):
    dist = [[INF for _ in range(w)] for _ in range(h)]
    q = deque()
    q.append((si, sj))
    dist[si][sj] = 0
    while len(q) > 0:
        i, j = q.popleft()
        for di, dj in [(1, 0), (-1, 0), (0, 1), (0, -1)]:
            ni = i + di
            nj = j + dj
            if 0 <= ni and ni < h and 0 <= nj and nj < w and C[ni][nj] != '#' and dist[i][j] + 1 < dist[ni][nj] and dist[i][j] + 1 <= abs(ni-si) + abs(nj-sj):
                dist[ni][nj] = dist[i][j] + 1
                q.append((ni, nj))
    return dist

def main():
    h, w = map(int, sys.stdin.readline().split())
    C = ["" for _ in range(h)]
    for i in range(h):
        C[i] = sys.stdin.readline()
    dist_S = bfs(0, 0, h, w, C)
    dist_G = bfs(h-1, w-1, h, w, C)
    if dist_S[h-1][w-1] == h+w-2:
        print(h+w-2)
        return
    
    is_max = 0
    js_max = 0
    for i in range(h):
        for j in range(w):
            if dist_S[i][j] == i+j:
                is_max = max(is_max, i)
                js_max = max(js_max, j)

    ig_min = h-1
    jg_min = w-1
    for i in range(h):
        for j in range(w):
            if dist_G[i][j] == h+w-2-i-j:
                ig_min = min(ig_min, i)
                jg_min = min(jg_min, j)

    if ig_min - is_max <= 1 or jg_min - js_max <= 1:
        print(h+w-1)
    else:
        print(h+w)

if __name__ == "__main__":
    main()