#yuki157

w,h=map(int,raw_input().split())
c=[list(raw_input()) for i in xrange(h)]
dx=[1,-1,0,0]
dy=[0,0,1,-1]
def dfs(x,y,t):
 c[y][x]=str(t)
 for i in xrange(4):
  if c[y+dy[i]][x+dx[i]]=='.':
   dfs(x+dx[i],y+dy[i],t)
cnt=0
for i in xrange(h):
 for j in xrange(w):
  if c[i][j]=='.':
   dfs(j,i,cnt)
   cnt+=1
res=float('inf')
for i in xrange(h):
 for j in xrange(w):
  if c[i][j]=='0':
   for k in xrange(h):
    for l in xrange(w):
     if c[k][l]=='1':
      res=min(res,abs(i-k)+abs(j-l)-1)
print res