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

int w, h;
vector<vector<int>> c;
void replace(int i, int j, int n) {
	if (c[i][j] == 1) {
		c[i][j] = n;
		replace(i + 1, j, n);
		replace(i - 1, j, n);
		replace(i, j + 1, n);
		replace(i, j - 1, n);
	}
	return;
}
int main() {
	cin >> w >> h;
	c.resize(h);
	for (int i = 0;i < h;i++) {
		string s;
		cin >> s;
		c[i].resize(w);
		for (int j = 0;j < w;j++) {
			if (s[j] == '#') {
				c[i][j] = 0;
			}
			else {
				c[i][j] = 1;
			}
		}
	}

	int count = 0;
	for (int i = 1;i < h-1;i++) {
		for (int j = 1;j < w-1;j++) {
			if (c[i][j] == 1) {
				replace(i, j, count + 2);
				count++;
			}
			if (count==2)
				break;
		}
		if (count == 2)
			break;
	}
	int mi = 20 * 20;
	for(int i=1;i<h-1;i++){
		for (int j = 1;j < w - 1;j++) {
			if (c[i][j] == 2) {
				for (int i2 = 1;i2 < h - 1;i2++) {
					for (int j2 = 1;j2 < w - 1;j2++) {
						if (c[i2][j2] == 3) {
							int d = abs(i - i2) + abs(j - j2)-1;
							mi = min(mi, d);
						}
					}
				}
			}
		}
	}
	cout << mi << endl;




	return 0;
}