#include <iostream>
#include<ctime>
#include<map>
#include<vector>
#include<queue>
#include <algorithm>
using namespace std;
int n, m;
char mat[105][105];
bool visited[105][105];
int bfs(int si, int sj, int ei, int ej) {
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            visited[i][j] = false;
        }
    }
    queue<int> q;
    q.push(si);
    q.push(sj);
    q.push(0);
    visited[si][sj] = true;
    while(!q.empty()) {
        int ci = q.front();
        q.pop();
        int cj = q.front();
        q.pop();
        int dist = q.front();
        q.pop();

        if(ci == ei and cj == ej) {
            return dist;
        }

        if(ci + 1 < n and !visited[ci + 1][cj] and mat[ci + 1][cj] != '#') {
            q.push(ci + 1);
            q.push(cj);
            q.push(dist + 1);
            visited[ci + 1][cj ] = true;
        }
        if(ci - 1 >= 0 and !visited[ci - 1][cj] and mat[ci - 1][cj] != '#') {
            q.push(ci - 1);
            q.push(cj);
            q.push(dist + 1);
            visited[ci - 1][cj ] = true;
        }
        if(cj + 1 < m and !visited[ci][cj + 1] and mat[ci][cj + 1] != '#') {
            q.push(ci);
            q.push(cj + 1);
            q.push(dist + 1);
            visited[ci][cj + 1] = true;
        }
        if(cj - 1 >= 0 and !visited[ci][cj - 1] and mat[ci][cj - 1] != '#') {
            q.push(ci);
            q.push(cj - 1);
            q.push(dist + 1);
            visited[ci][cj- 1 ] = true;
        }
    }
    return -1;
}
int main()
{
    cin >> n >> m;
    pair<int, int> idx[5];
    int tmp = 1;
    int drinks = 0;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            cin >> mat[i][j];

            if(mat[i][j] == 'S'){
                idx[0] = make_pair(i, j);
            }
            if(mat[i][j] == 'D') {
                idx[tmp] = make_pair(i, j);
                drinks++;
                tmp++;
            }
            if(mat[i][j] == 'B') {
                idx[4] = make_pair(i, j);
            }
        }
    }
    int perm[drinks + 1];
    for(int i = 0; i < drinks; i++) {
        perm[i] = i + 1;
    }
    int si = idx[0].first;
    int sj = idx[0].second;

    int bi = idx[4].first;
    int bj = idx[4].second;
    int result = 2e9;
    do {
        int p = 0;
        for(int i = 0; i < drinks; i++) {
            if(i == 0) {
                int x = bfs(si, sj, idx[perm[i]].first, idx[perm[i]].second);
                if(x == -1) {
                    cout << -1 << endl;
                    return 0;
                }
                p += x;
            }
            else {
                int x = bfs(idx[perm[i - 1]].first, idx[perm[i - 1]].second, idx[perm[i]].first, idx[perm[i]].second);
                if(x == -1) {
                    cout << -1 << endl;
                    return 0;
                }
                p += x;
            }
        }
        int x= bfs(idx[perm[drinks - 1]].first, idx[perm[drinks - 1]].second, bi, bj)
        ;
        if(x == -1) {
            cout << -1 << endl;
            return 0;
        }
        p += x;
        if(result > p) {
            result = p;
        }

    } while(next_permutation(perm, perm + drinks));
    cout << result << endl;
    // S 1 2 3 B
    return 0;
}