/* Bismillahir Rahmanir Rahim */
                                   /*Coder: Arman Kamal*/

                        /* Just do not stop. If you stop, you stop learning. So, do not stop*/

#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

# define FOR(i, a, b) for (int i=a; i<b; i++)
# define REP(i, a) FOR(i,0,a)

#define EPS 1e-20
#define inf ( 1LL << 30 )
#define LL long long

#define abs(x) (((x)< 0) ? (-(x)) : (x))
#define all(x) (x).begin(), (x).end()
#define ms(x, a) memset((x), (a), sizeof(x))

# define VI vector<int>
# define VS vector<string>
# define VC vector<char>
# define pii pair<int,int>

#define mp make_pair
#define pb push_back
#define CI(x) scanf(" %d", &x)
#define CL(x) scanf(" %lld", &x)
#define READ(x) freopen(x,"r",stdin)

using namespace std;

#define PI 2*acos(0.0)

int r , c , x , y;
pii st;
char grid[205][205];
int fire[205][205];
int cost[205][205];

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

vector<pii> f;

void fbfs(pii src){
    queue <pii> q;
    q.push(src);
    fire[src.first][src.second] = 0;
    while(!q.empty()){
        pii p = q.front();q.pop();

            for(int i = 0 ; i < 4 ; i++){
               x = p.first + dx[i];
               y = p.second + dy[i];
               if(x >= 0 && y >= 0 && x < r && y < c ){
                   if(fire[x][y] > fire[p.first][p.second] + 1){
                        fire[x][y] = fire[p.first][p.second] + 1;
                        q.push(mp(x,y));
                   }
               }
            }

    }
}

int bfs(pii src){
    queue <pii> q;
    q.push(src);
    cost[src.first][src.second] = 0;
    while(!q.empty()){
        pii p = q.front();q.pop();

            for(int i = 0 ; i < 4 ; i++){
               x = p.first + dx[i];
               y = p.second + dy[i];
               if(grid[x][y] == '#') continue;

               if(x >= 0 && y >= 0 && x < r && y < c){
                   if(cost[x][y] == -1 && fire[x][y] > cost[p.first][p.second] + 1){
                        cost[x][y] = cost[p.first][p.second] + 1;
                        q.push(mp(x,y));
                   }
               }else{
                return cost[p.first][p.second] + 1;
               }
            }

    }
    return -1;
}


int main(){
//    freopen("x.txt", "r", stdin);
    int t , cas = 0, cst ;
    scanf(" %d", &t);
    while(t--){
        f.clear();

        scanf(" %d %d", &r ,&c);

        REP(i , 205){
            REP(j , 205){
                cost[i][j] = -1;
                fire[i][j] = inf;
            }
        }

        REP(i , r){
            REP(j , c){
                scanf(" %c",&grid[i][j]);
                char &c = grid[i][j];
                if(c == 'F')f.pb(mp(i,j));
                else if(c == 'J')st = mp(i,j);
            }
        }

        REP(i,f.size()){
            fbfs(f[i]);
        }

        cst = bfs(st);


        printf("Case %d: ", ++cas);
        if(cst != -1)printf("%d\n",cst);
        else printf("IMPOSSIBLE\n");

    }

return 0;
}