def main():
    w, h = map(int, input().split())
    c = [input() for i in range(h)]

    k1, k2 = set(), set()
    for i in range(h):
        for j in range(w):
            if c[i][j] == ".":
                if (i-1, j) in k1 or (i, j-1) in k1:
                    k1.add((i, j))
                elif (i-1, j) in k2 or (i, j-1) in k2:
                    k2.add((i, j))
                elif len(k1) == 0:
                    k1.add((i, j))
                elif len(k2) == 0:
                    k2.add((i, j))

    min_num = 100
    lst1, lst2 = list(k1), list(k2)
    for i in range(len(lst1)):
        for j in range(len(lst2)):
            if abs(lst1[i][0]-lst2[j][0]) + abs(lst1[i][1]-lst2[j][1]) < min_num:
                min_num = abs(lst1[i][0]-lst2[j][0]) + abs(lst1[i][1]-lst2[j][1])

    print(min_num-1)


if __name__ == '__main__':
    main()