int br,bc;

int pr,pc;

int step;

int id;

int walk;

if(_r<0 || _r>=r || _c<0 || _c>=c|| maze[_r][_c]=='#'){

return false;

}return true;

if(pre[cur][0]==-1){

return ;

}

ans_path+=moves[ pre[cur][1] ];

get_path(pre[cur][0]);

if(vis[cur.br][cur.bc][cur.pr][cur.pc]){

return true;

}return false;

memset(pre,-1,sizeof(pre));

global_cnt = 0;

ans_path = "";

node start;

start.br = b_r, start.bc = b_c, start.pr = p_r, start.pc = p_c, start.step=0, start.id = global_cnt++, start.walk=1;

queue<node> Q;

Q.push(start);

int ans = -1;

node cur, next;

int ans_state;

vis[start.br][start.bc][start.pr][start.pc] = 1;

while(!Q.empty()){

cur = Q.front();

Q.pop();

//cout<<"people at "<<cur.pr<<" "<<cur.pc<<", box at "<<cur.br<<" "<<cur.bc<<endl;

//print(cur);

if(cur.br == e_r && cur.bc == e_c){

ans = cur.step;

ans_state = cur.id;

break;

}

int nr, nc, nbr, nbc,nstep,nwalk;

nbr = cur.br, nbc = cur.bc;

for(int i=0; i<4; i++){

nr = cur.pr+dir[i][0];

nc = cur.pc+dir[i][1];

if(check(nr,nc)){

//move box

bool move_box=false;

if(nr==cur.br && nc==cur.bc){

nbr= cur.br+dir[i][0];

nbc= cur.bc+dir[i][1];

move_box = true;

//cout<<"move to "<<nbr<<" "<<nbc<<endl;

if(!check(nbr, nbc)){

move_box = false;

nbr = cur.br, nbc = cur.bc, nr = cur.pr, nc = cur.pc, nstep--;

}

}else{

nbr = cur.br, nbc = cur.bc;

}

if(move_box){

nstep = cur.step+1;

}else{

nstep = cur.step;

}

nwalk = cur.walk+1;

next.pr = nr, next.pc = nc, next.br = nbr, next.bc = nbc, next.step = nstep, next.walk = nwalk;

if(is_in(next)==false){

next.id = global_cnt++;

Q.push(next);

vis[next.br][next.bc][next.pr][next.pc] = 1;

if(move_box){

pre[next.id][0] = cur.id;

pre[next.id][1] = i;

//next.path = cur.path+move_path[i];

}else{

pre[next.id][0] = cur.id;

pre[next.id][1] = i+4;

//next.path = cur.path+no_move_path[i];

}

//cout<<"pre of "<<next.id <<" is "<<cur.id<<endl;

}

}

}

}

if(ans==-1){

cout<<"Impossible."<<endl;

}else{

get_path(ans_state);

reverse(ans_path.begin(), ans_path.end());

cout<<ans_path<<endl;

}

int cnt_case = 1;

//while(scanf("%d%d",&r,&c)!=EOF){

while(cin>>r>>c){

if(r==0&&c==0)break;

// getchar();

//cout<<"r and c are "<<r<<" "<<c<<endl;

for(int i=0; i<r; i++){

cin>>maze[i];

for(int j=0; j<c; j++){

// scanf("%c",&maze[i][j]);

if(maze[i][j]=='T'){

e_r = i, e_c = j;

}else if(maze[i][j]=='B'){

b_r = i, b_c = j;

}else if(maze[i][j]=='S'){

p_r = i, p_c = j;

// cout<<"people at "<<p_r<<" "<<p_c<<endl;

}

}

//getchar();

}

/*

cout<<"Maze #"<<cnt_case<<endl;

work();

cnt_case++;

cout<<endl;

}

return 0;