from itertools import product


def main():
    w, h = map(int, input().split())
    g = [list(input()) for _ in range(h)]

    def dfs(x, y):
        g[x][y] = '#'
        yield [x, y]

        dx = [1, 0, -1, 0, 1, -1, -1, 1]
        dy = [0, 1, 0, -1, 1, 1, -1, -1]
        for dx, dy in zip(dx[:4], dy[:4]):
            nx = x + dx
            ny = y + dy
            if not (0 <= nx < h and 0 <= ny < w):
                continue
            if g[nx][ny] == '.':
                yield from dfs(nx, ny)

    cave1, cave2 = [], []
    is_first = True
    for i, j in product(range(h), range(w)):
        if g[i][j] == '.':
            if is_first:
                cave1 = list(dfs(i, j))
                is_first = False
            else:
                cave2 = list(dfs(i, j))
                break

    ans = 1 << 60
    for x1, y1 in cave1:
        for x2, y2 in cave2:
            ans = min(ans, abs(x1 - x2) + abs(y1 - y2) - 1)
    print(ans)


if __name__ == "__main__":
    main()