#!/usr/bin/env python3
# -*- coding: utf-8 -*-

w, h = map(int,input().split())
c = [list(input()) for j in range(h)]

dx = [ 1, 0,-1, 0]
dy = [ 0, 1, 0,-1]

nx = 0
ny = 0

cnt = 0

def dfs(x,y,count):
    c[y][x] = str(count)
    for k in range(4):
        if c[y+dy[k]][x+dx[k]] == ".":
            dfs(x+dx[k], y+dy[k], count)

for j in range(h):
    for i in range(w):
        if c[j][i] == ".":
            dfs(i, j, cnt)
            cnt += 1

ans = 10**9
for j in range(h):
    for i in range(w):
        if c[j][i] == "0":
            for l in range(h):
                for k in range(w):
                    if c[l][k] == "1":
                        ans = min(ans, abs(j-l) + abs(i-k))

print(ans-1)