#include<cstdio> #include<cstdlib> #include<cstring> #include<cmath> #include<ctime> #include<cctype> #include<climits> #include<iostream> #include<string> #include<vector> #include<map> #include<list> #include<queue> #include<deque> #include<algorithm> #include<numeric> #include<utility> #include<complex> #include<memory> #include<functional> using namespace std; #define ALL(g) (g).begin(),(g).end() #define REP(i, x, n) for(int i = x; i < n; i++) #define rep(i,n) REP(i,0,n) #define F(i,j,k) fill(i[0],i[0]+j*j,k) #define P(p) cout<<(p)<<endl; #define EXIST(s,e) ((s).find(e)!=(s).end()) #define INF 1<<25 #define pb push_back typedef vector<int> vi; typedef vector<long long> vl; typedef vector<double> vd; typedef pair<int,int> pii; typedef pair<long,long> pll; typedef long long ll; int W,H,cnt=0; vector<string> c; void dfs(int y,int x,int z){ c[y][x]=cnt; if(c[y][x-1]=='.')dfs(y,x-1,cnt); if(c[y][x+1]=='.')dfs(y,x+1,cnt); if(c[y-1][x]=='.')dfs(y-1,x,cnt); if(c[y+1][x]=='.')dfs(y+1,x,cnt); } int main(){ cin>>W>>H; for(int i=0;i<H;i++){ string tmp; cin>>tmp; c.push_back(tmp); } for(int i=0;i<H;i++){ for(int j=0;j<W;j++){ if(c[i][j]=='.'){ dfs(i,j,cnt); cnt++; } } } int ans=40; for(int i=0;i<H;i++) for(int j=0;j<W;j++) for(int k=0;k<H;k++) for(int l=0;l<W;l++) if(c[i][j]==0&&c[k][l]==1) ans=min(ans,abs(i-k)+abs(j-l)); ans--; cout<<ans<<endl; return 0; }