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

int W, H;
string C[30];

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

void f(int x, int y) {
    if (x < 0 || y < 0 || x >= H || y >= W)
        return;
    if (C[x][y] == '.') {
        C[x][y] = '?';
        for (int i = 0; i < 4; i++) {
            f(x + dx[i], y + dy[i]);
        }
    }
}


int main() {
    cin >> W >> H;
    for (int i = 0; i < H; i++) {
        cin >> C[i];
    }

    bool flag = false;
    for (int x = 0; x < H; x++) {
        for (int y = 0; y < W; y++) {
            if (C[x][y] == '.') {
                flag = true;
                f(x, y);
            }
            if (flag)
                break;
        }
        if (flag)
            break;
    }


    int ans = 100;
    for (int x1 = 0; x1 < H; x1++) {
        for (int x2 = 0; x2 < H; x2++) {
            for (int y1 = 0; y1 < W; y1++) {
                for (int y2 = 0; y2 < W; y2++) {
                    if (C[x1][y1] == '.' && C[x2][y2] == '?')
                        ans = min(ans, abs(x1 - x2) + abs(y1 - y2) - 1);
                }
            }
        }
    }

    cout << ans << endl;
}