#include <cstdio>

 #include <cstring>

 #include <queue>

 using namespace std;

 struct Node

 {

     int x, y, t;

     Node(int x=, int y=, int t=):x(x), y(y), t(t) {}

 };

 Node st;

 const int maxn =  + ;

 int row, col;

 char maze[maxn][maxn];

 int time[maxn][maxn];

 bool vis[maxn][maxn];

 int dx[] = { , , , - };

 int dy[] = { , , -,  };

 inline bool in(int x, int y)

 { return x >=  && x < row && y >=  && y < col; }

 inline bool border(int x, int y)

 { return x ==  || x == row- || y ==  || y == col-; }

 void init()

 {

     memset(time, -, sizeof(time));

     queue<Node> Q;

     for(int i = ; i < row; i++)

         for(int j = ; j < col; j++)

         {

             if(maze[i][j] == 'F') { Q.push(Node(i, j, )); time[i][j] = ; }

             if(maze[i][j] == 'J') { st.x = i; st.y = j; st.t = ; }

         }

     while(!Q.empty())

     {

         Node now = Q.front(); Q.pop();

         for(int i = ; i < ; i++)

         {

             int x = now.x + dx[i];

             int y = now.y + dy[i];

             int t = now.t + ;

             if(in(x, y) && time[x][y] <  && maze[x][y] != '#')

             {

                 Q.push(Node(x, y, now.t + ));

                 time[x][y] = t;

             }

         }

     }

 }

 int BFS()

 {

     memset(vis, false, sizeof(vis));

     queue<Node> Q;

     Q.push(st);

     vis[st.x][st.y] = true;

     while(!Q.empty())

     {

         Node now = Q.front(); Q.pop();

         if(border(now.x, now.y)) return now.t + ;

         for(int i = ; i < ; i++)

         {

             int x = now.x + dx[i];

             int y = now.y + dy[i];

             int t = now.t + ;

             if(in(x, y) && !vis[x][y] && maze[x][y] != '#')

             {

                 if(time[x][y] >=  && time[x][y] <= t) continue;

                 vis[x][y] = true;

                 Q.push(Node(x, y, t));

             }

         }

     }

     return ;

 }

 int main()

 {

     //freopen("in.txt", "r", stdin);

     int T; scanf("%d", &T);

     while(T--)

     {

         scanf("%d%d", &row, &col);

         for(int i = ; i < row; i++) scanf("%s", maze[i]);

         init();

         int ans = BFS();

         if(ans) printf("%d\n", ans);

         else puts("IMPOSSIBLE");

     }

     return ;

 }