#include <bits/stdc++.h>

using namespace std;

typedef pair<int,int> P;
typedef pair<int,pair<int,int>> PP;
typedef long long ll;

const double EPS = 1e-8;
const int INF = 1e9;
const int MOD = 1e9+7;

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

int prim(int n,vector<vector<int>>&c){
	n--;
	vector<int> mincost(n);
	vector<bool> used(n);
	for(int i=0;i<n;i++){
		mincost[i] = INF+1;
		used[i] = false;
	}

	mincost[0] = 0;
	int res = 0;
	for(;;){
		int v = -1;
		for(int u=0;u<n;u++){
			if(!used[u] && (v==-1 || mincost[u] < mincost[v]))v = u;
		}
		if(v==-1)break;
		used[v] = true;
		res += mincost[v];

		for(int u=0;u<n;u++){
			mincost[u] = min(mincost[u],c[v][u]);
		}
		//cout << v << ":" << res << endl;
	}
	return res;
}

vector<string> vs;
bool dfs(int i,int j,int a,vector<vector<int>>& c){
	if(vs[i][j] == '.' && c[i][j] == -1){
		c[i][j] = a;
		for(int k=0;k<4;k++){
			dfs(dy[k]+i,dx[k]+j,a,c);
		}
		return true;
	}
	else return false;
}

int main(void) {
	int w,h;
	cin >> w >> h;
	vs.resize(h);
	vector<vector<int>> c(h,vector<int>(w,-1));
	for(int i=0;i<h;i++){
		cin >> vs[i];
	}

	int cnt = 0;
	for(int i=0;i<h;i++){
		for(int j=0;j<w;j++){
			if(dfs(i,j,cnt,c))cnt++;
		}
	}

	vector<vector<int>> dist(cnt+1,vector<int>(cnt+1,INF));
	for(int i=0;i<cnt+1;i++)dist[i][i] = 0;
	for(int i=0;i<h;i++){
		for(int j=0;j<w;j++){
			for(int l=0;l<h;l++){
				for(int m=0;m<w;m++){
					int a = c[i][j];
					int b = c[l][m];
					if(a != -1 && b != -1 && a != b){
						int d = abs(i-l)+abs(j-m)-1;
						dist[b][a] = dist[a][b] = min(dist[a][b],d);
					}
				}
			}
		}
	}
	cout << prim(cnt+1,dist) << endl;

	return 0;
}