from collections import deque


def main():
    H, W = map(int, input().split())
    S = []
    for _ in range(H):
        S.append(input())

    que = deque([(0, 0)])
    isvisited = [[False for _ in range(W - 2)] for _ in range(H - 2)]
    isvisited[0][0] = True
    dx = [1, 1, 0, -1, -1, -1, 0, 1]
    dy = [0, 1, 1, 1, 0, -1, -1, -1]

    pos = [[True for _ in range(W - 2)] for _ in range(H - 2)]
    for i in range(H - 2):
        for j in range(W - 2):
            for k in range(3):
                for l in range(3):
                    if S[i + k][j + l] == "#":
                        pos[i][j] = False

    while que:
        p = que.popleft()
        for i in range(8):
            if 0 <= p[0] + dx[i] < H - 2 and 0 <= p[1] + dy[i] < W - 2:
                if isvisited[p[0] + dx[i]][p[1] + dy[i]]:
                    continue
                if pos[p[0] + dx[i]][p[1] + dy[i]]:
                    isvisited[p[0] + dx[i]][p[1] + dy[i]] = True
                    que.append((p[0] + dx[i], p[1] + dy[i]))

    if not isvisited[H - 3][W - 3]:
        print(0)
        return

    for i in range(H):
        for j in range(W):
            if S[i][j] == "#":
                continue
            if 0 <= i <= 2 and 0 <= j <= 2:
                continue
            if H - 3 <= i < H and W - 3 <= j < W:
                continue
            S[i] = S[i][:j] + "#" + S[i][j + 1 :]
            que.append((0, 0))
            for k in range(H - 2):
                for l in range(W - 2):
                    isvisited[k][l] = False

            isvisited[0][0] = True
            for k in range(H - 2):
                for l in range(W - 2):
                    pos[k][l] = True
            for k in range(H - 2):
                for l in range(W - 2):
                    for m in range(3):
                        for n in range(3):
                            if S[k + m][l + n] == "#":
                                pos[k][l] = False

            while que:
                p = que.popleft()
                for k in range(8):
                    if 0 <= p[0] + dx[k] < H - 2 and 0 <= p[1] + dy[k] < W - 2:
                        if isvisited[p[0] + dx[k]][p[1] + dy[k]]:
                            continue
                        if pos[p[0] + dx[k]][p[1] + dy[k]]:
                            isvisited[p[0] + dx[k]][p[1] + dy[k]] = True
                            que.append((p[0] + dx[k], p[1] + dy[k]))

            if not isvisited[H - 3][W - 3]:
                print(1)
                return

            S[i] = S[i][:j] + "." + S[i][j + 1 :]

    print(2)


if __name__ == "__main__":
    main()