#include <bits/stdc++.h>
typedef long long ll;
#define INF 1000000000
#define MOD 1000000007
using namespace std;
int dx[4]={1,0,-1,0},dy[4]={0,-1,0,1};
int main(void){
    int w,h;
    cin>>w>>h;
    vector<vector<char> >c(h,vector<char>(w));
    vector<vector<char> >tmp(h,vector<char>(w));
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            cin>>c[i][j];
            tmp[i][j]=c[i][j];
        }
    }
    vector<pair<int,int> >pool,sea;
    bool ok=true;
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            if(tmp[i][j]=='.'){
                if(ok){
                ok=false;
                int sx=j,sy=i;
                queue<pair<int,int> > que;
                que.push(pair<int,int>(sy,sx));
                while(!que.empty()){
                pair<int ,int>t=que.front();
                pool.push_back({t.first,t.second});
                tmp[t.first][t.second]='#';
                que.pop();
                for(int i=0;i<4;i++){
                     int ny=t.first+dy[i];
                     int nx=t.second+dx[i];
                     if(nx>=0&&nx<w&&ny>=0&&ny<h&&tmp[ny][nx]=='.'){
                         que.push(pair<int,int>(ny,nx));
            }

        }
    }
                }else if(ok==false){
                int sx=j,sy=i;
                queue<pair<int,int> > que;
                que.push(pair<int,int>(sy,sx));
                while(!que.empty()){
                pair<int ,int>t=que.front();
                sea.push_back({t.first,t.second});
                tmp[t.first][t.second]='#';
                que.pop();
                for(int i=0;i<4;i++){
                     int ny=t.first+dy[i];
                     int nx=t.second+dx[i];
                     if(nx>=0&&nx<w&&ny>=0&&ny<h&&tmp[ny][nx]=='.'){
                         que.push(pair<int,int>(ny,nx));
            }

        }
    }

                }

            }
        }
    }
    /*
    for(int i=0;i<pool.size();i++){
        cout<<pool[i].first<<" "<<pool[i].second<<endl;
    }
    for(int i=0;i<sea.size();i++){
        cout<<sea[i].first<<" "<<sea[i].second<<endl;
    }
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            cout<<tmp[i][j];
        }
        cout<<endl;
    }
    */
    int min_dist=INF;
    pair<int,int>ans;
    for(int i=0;i<pool.size();i++){
        for(int j=0;j<sea.size();j++){
            pair<int,int>a,b;
            int tmp,xdiff,ydiff;
            a=pool[i];
            b=sea[j];
            xdiff=abs(a.first-b.first);
            ydiff=abs(a.second-b.second);
            tmp=xdiff+ydiff-1;
            if(tmp<min_dist){
                min_dist=tmp;
            }

        }
    }
    cout<<min_dist<<endl;
}