#include <bits/stdc++.h>


using namespace std;

const int INF = INT_MAX;




int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int R, C;
    char mat[100][100];
    int dist[100][100];
    int drink_dist[4][4];
    int dx[] = {1, -1, 0, 0};
    int dy[] = {0, 0, 1, -1};
    vector<pair<int, int>> points;
    cin >> R >> C;

    pair<int, int> start, beach;
    vector<pair<int, int>> drinks;


    for (int i = 0; i < R; i++) {
        for (int j = 0; j < C; j++) {
            cin >> mat[i][j];
            if (mat[i][j] == 'S') {
                start = {i, j};
            } else if (mat[i][j] == 'B') {
                beach = {i, j};
            } else if (mat[i][j] == 'D') {
                drinks.push_back({i, j});
            }
        }
    }

    points.push_back(start);
    for (auto d : drinks) points.push_back(d);
    points.push_back(beach);

    auto bfs = [&](int start_idx) {
        queue<pair<int, int>> q;
        int start_x = points[start_idx].first;
        int start_y = points[start_idx].second;

        for (int i = 0; i < R; i++) {
            for (int j = 0; j < C; j++) {
                dist[i][j] = INF;
            }
        }

        dist[start_x][start_y] = 0;
        q.push({start_x, start_y});

        while (!q.empty()) {
            int x = q.front().first;
            int y = q.front().second;
            q.pop();

            for (int dir = 0; dir < 4; dir++) {
                int nx = x + dx[dir];
                int ny = y + dy[dir];

                if (nx >= 0 && nx < R && ny >= 0 && ny < C && mat[nx][ny] != '#' && dist[nx][ny] == INF) {
                    dist[nx][ny] = dist[x][y] + 1;
                    q.push({nx, ny});
                }
            }
        }

        for (int i = 0; i < points.size(); i++) {
            drink_dist[start_idx][i] = dist[points[i].first][points[i].second];
        }
    };

    for (int i = 0; i < points.size(); i++) {
        bfs(i);
    }

    vector<int> order;
    for (int i = 1; i <= drinks.size(); i++) {
        order.push_back(i);
    }

    int min_steps = INF;

    do {
        int current_steps = drink_dist[0][order[0]];
        for (int i = 1; i < order.size(); i++) {
            current_steps += drink_dist[order[i-1]][order[i]];
        }
        current_steps += drink_dist[order.back()][points.size() - 1];
        min_steps = min(min_steps, current_steps);
    } while (next_permutation(order.begin(), order.end()));

    if (min_steps >= INF) {
        cout << -1 << endl;
    } else {
        cout << min_steps << endl;
    }

    return 0;
}