J

//两遍bfs
#include<bits/stdc++.h>

using namespace std;

const int MAXN = 1010;

int n,m;
char G[MAXN][MAXN];
int fire[MAXN][MAXN];
int Time[MAXN][MAXN];
int dir[4][2] = {{0,1},{0,-1},{1,0},{-1,0}};

struct node{
    int x, y;
}last, now;

void bfs_Fire(){
    memset(fire,-1,sizeof(fire));
    queue< node > q;
    for(int i = 0 ; i<n ; i++){
        for(int j = 0 ; j<m ; j++){
            if(G[i][j] == 'F'){
                fire[i][j] = 0;
                last.x = i;
                last.y = j;
                q.push(last);
            }
        }
    }
    while(!q.empty()){
        last = q.front();
        q.pop();

        for(int i = 0 ; i<4 ; i++){
            now.x = last.x + dir[i][0];
            now.y = last.y + dir[i][1];

            if(now.x<0 || now.x>=n || now.y<0 || now.y>=m)
                continue;
            if(fire[now.x][now.y]!=-1)
                continue;
            if(G[now.x][now.y] == '#')
                continue;

            fire[now.x][now.y] = fire[last.x][last.y] + 1;
            q.push(now);
        }
    }
}

int bfs(){
    queue< node > q;
    memset(Time,-1,sizeof(Time));
    for(int i = 0 ; i<n ; i++){
        for(int j = 0 ; j<m ; j++){
            if(G[i][j] == 'J'){
                last.x = i;
                last.y = j;
                q.push(last);
                Time[i][j] = 0;
            }
        }
    }

    while (!q.empty()){
        last = q.front();
        q.pop();

        if(last.x==0 || last.y==0 || last.x==n-1 || last.y==m-1)
            return Time[last.x][last.y]+1;

        for(int i = 0 ; i<4 ; i++){
            now.x = last.x+dir[i][0];
            now.y = last.y+dir[i][1];

            if(Time[now.x][now.y] != -1)
                continue;
            if(now.x<0 || now.x>=n || now.y<0 || now.y>=m)
                continue;
            if(G[now.x][now.y] == '#')
                continue;
            if(fire[now.x][now.y]!=-1 && Time[last.x][last.y]+1>=fire[now.x][now.y])
                continue;

            Time[now.x][now.y] = Time[last.x][last.y] + 1;
            q.push(now);
        }
    }
    return -1;
}

int main(){
    int T;
    scanf("%d",&T);
    while (T--){
        scanf("%d %d",&n,&m);
        for(int i = 0 ; i<n ; i++){
            scanf("%s",G[i]);
        }
        bfs_Fire();

        int ans = bfs();
        if(ans == -1)
            printf("IMPOSSIBLE
");
        else
            printf("%d
",ans);
    }
    return 0;
}