# include <iostream>
# include <fstream>
# include <cstring>
# include <queue>
# include <vector>
using namespace std;
struct Info
{
    int x, y, jishu;
}info;
int m, n;
char map[101][101];
int is[101][101];
int dx[4] = {1,0,-1,0};
int dy[4] = {0,-1,0,1};

vector <Info> v;


int bfs();
bool border(Info & a)
{
    if(a.x >= 1 && a.x <= m && a.y >= 1 && a.y <= n)
    return true;
    return false;
}
int main()
{
    //fstream cin("aaa.txt");
    while(cin >> m >> n)
    {
        v.clear();
        if(m == 0 && n == 0) break;
        for(int i = 1; i <= m; i++)
            for(int j = 1; j <= n; j++)
            {
                cin >> map[i][j];
                if(map[i][j] == ‘D‘)
                {
                    info.x = i;
                    info.y = j;
                    info.jishu = 0;
                    v.push_back(info);
                }
            }
            int h = bfs();
            if(h < 0)
            cout << "Impossible" << endl;
            else
            cout << h << endl;
    }

    return 0;
}
int bfs()
{
    is[v[0].x][v[0].y] = 1;
    memset(is, 0, sizeof(is));
    queue <vector <Info> > Q; 
    Q.push(v);
    vector <Info> now, next;
    while(!Q.empty())
    {
        now = Q.front();
        Q.pop();

        for(int i = 0; i < 4; i++)
        {
            next = now;
            next[0].jishu ++;

            for(int j = 0; j < next.size(); j++)
            {
                next[j].x = now[j].x + dx[i];
                next[j].y = now[j].y + dy[i];
            }
            int flag = 0;
            for(int j = 0; j < next.size(); j++)
            {
                if(!border(next[j]) || map[next[j].x][next[j].y] == ‘O‘)
                flag = 1;
               // cout << map[next[j].x][next[j].y];
            }
            //cout << endl;
            if(flag)
            continue;
            if(is[next[0].x][next[0].y])
            continue;
            for(int j = 0; j < next.size(); j++)
                if(map[next[j].x][next[j].y] == ‘Q‘)
                    return next[0].jishu;

            is[next[0].x][next[0].y] = 1;
            Q.push(next);
        }

    }
    return -1;

}