#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include <algorithm>
#include <utility>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <functional>

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef vector<pii> vpii;

#define fst first
#define scd second
#define PB push_back
#define MP make_pair
#define rep(i,x) for(int i=0;i<(x);++i)
#define rep1(i,x) for(int i=1;i<=(x);++i)
#define rrep(i,x) for(int i=(x)-1;i>=0;--i)
#define rrep1(i,x) for(int i=(x);i>=1;--i)
#define FOR(i,a,x) for(int i=(a);i<(x);++i)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()

#define omajinai ios::sync_with_stdio(false);cin.tie(0)

template<typename T>bool chmax(T&a,T b){if(a<b){a=b;return true;}return false;}
template<typename T>bool chmin(T&a,T b){if(a>b){a=b;return true;}return false;}
template<typename T>T get(){T a;cin>>a;return a;}
template<typename T>T rev(T a){reverse(all(a));return a;}
template<typename T>istream&operator>>(istream&is,vector<T>&vec){rep(i,vec.size())is>>vec[i];return is;}
template<typename T>vector<T>&sort(vector<T>&a){sort(all(a));return a;}

const int inf = 1e9;
const ll linf = 3e18;
const double eps = 1e-9;

int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, -1, 0, 1};

int W, H;
char C[22][22];
vpii crd[2];

void dfs(int t, int y, int x)
{
    C[y][x] = t + '0';
    crd[t].push_back(pii(y, x));

    rep(i, 4) {
        int ny = y + dy[i], nx = x + dx[i];
        if (ny < 0 || ny >= H || nx < 0 || nx >= W) continue;
        if (C[ny][nx] == '.') {
            dfs(t, ny, nx);
        }
    }
}

int calc(pii p1, pii p2)
{
    if (p1.fst == p2.fst) {
        return abs(p1.scd - p2.scd) - 1;
    }
    if (p1.scd == p2.scd) {
        return abs(p1.fst - p2.fst) - 1;
    }
    return abs(p1.fst - p2.fst) + abs(p1.scd - p2.scd) - 1;
}

signed main()
{
    cin >> W >> H;

    rep(i, H) rep(j, W) cin >> C[i][j];

    int type = 0;
    rep(i, H) rep(j, W) {
        if (C[i][j] == '.') {
            dfs(type, i, j);
            ++ type;
        }
    }

    int mi = inf;

    rep(i, crd[0].size()) rep(j, crd[1].size()) {
        pii p1 = crd[0][i], p2 = crd[1][j];
        chmin(mi, calc(p1, p2));
    }

    cout << mi << endl;
}