#include <bits/stdc++.h>
using namespace std;

// 基本テンプレート
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
#define P(x) cout << (x) << endl
#define p(x) cout << (x)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define mat(type, c, m, n) vector<vector<type>> c(m, vector<type>(n));for(auto& r:c)for(auto& i:r)cin>>i;
#define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
#define rrep(i,a,n) for(int i=(a); i>n; --i)
#define each(x,y) for(auto &(x):(y))
#define perm(c) sort(all(c));for(bool c##p=1;c##p;c##p=next_permutation(all(c)))
#define cauto const auto&
#define UNIQUE(v) v.erase( unique(all(v)), v.end() );
#define len(x) ((int)(x).size())
#define length(a)   (sizeof(a)/sizeof(a[0]))
inline void print() {cout << endl;}
template <class H, class... T> inline void print(H h, T... t){cout << h << " ";print(t...);}
#define dbg(v) for(auto i : v) cout << i << " "; cout << endl;

// 型
typedef long long ll;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long long> vll;
typedef vector<string> vs;

ll mod = (int)1e9 + 7;

// 定数
#define PI acos(-1.0)
constexpr int EPS = (1e-9);
constexpr int INF = 100000000;

// 4近傍
int dx[]={1, 0, -1, 0};
int dy[]={0, 1, 0, -1};
// 8近傍
//constexpr int dy[]={0,0,1,-1,1,1,-1,-1};
//constexpr int dx[]={1,-1,0,0,1,-1,1,-1};

int nx = 0, ny = 0, cnt = 0;
int w, h;
vs c;

void dfs(int x, int y, int count) {
	c[y][x] = '0' + count;
	rep(i, 0, 4) {
		if(c[y + dy[i]][x + dx[i]] == '.')
			dfs(x + dx[i], y + dy[i], count);
	}
}

int main() {
//	cout << setprecision(12) << fixed;

	cin >> w >> h;
	rep(i, 0, h) { string s; cin >> s; c.push_back(s); }

	rep(j, 0, h) {
		rep(i, 0, w) {
			if (c[j][i] == '.') {
				dfs(i, j, cnt);
				++cnt;
			}
		}
	}

	int ans = 1e9;
	rep(j, 0, h) {
		rep(i, 0, w) {
			if(c[j][i] == '0') {
				rep(l, 0, h) {
					rep(k, 0, w) {
						if(c[l][k] == '1')
							ans = min(ans, abs(j - l) + abs(i - k));
					}
				}
			}
		}
	}

	P(ans - 1);

	return 0;
}