#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
#include<queue>
#include<cstring>
#include<string>
#include<cstring>
using namespace std;
#define inf 0x3f3f3f
char a[1005][1005];
int dis[1005][1005];
int n,m,jx,jy;
int nex[4][2]= {{0,1},{1,0},{0,-1},{-1,0} };
typedef struct
{
    int x,y;
} Point;
int boundary(int x,int y)
{
    return (x>=0&&x<n&&y>=0&&y<m) ;

}
int judge(int x,int y)
{
    return (x==0||y==0||x==n-1|y==m-1);
}
void fire_bfs()
{
    queue<Point>q;
    Point f1,f2;
    memset(dis,inf,sizeof(dis));
    for(int i=0; i<n; i++)
        for(int j=0; j<m; j++)
        {
            if(a[i][j]==‘F‘)
            {
                f1.x=i,f1.y=j;
                dis[i][j]=0;
                q.push(f1);
            }
        }

    while(!q.empty())
    {
        f1=q.front();
        q.pop();
        for(int i=0; i<4; i++)
        {
            f2.x=f1.x+nex[i][0];
            f2.y=f1.y+nex[i][1];
            if(boundary(f2.x,f2.y)&&a[f2.x][f2.y]==‘.‘&&dis[f2.x][f2.y]>dis[f1.x][f1.y]+1)
            {
                dis[f2.x][f2.y]=dis[f1.x][f1.y]+1;
                q.push(f2);
            }
        }
    }

}
int bfs()
{
    queue<Point>q;
    Point f1,f2;
    f1.x=jx,f1.y=jy;
    dis[jx][jy]=0;
    q.push(f1);
    while(!q.empty())
    {
        f1=q.front();
        if(judge(f1.x,f1.y)) return dis[f1.x][f1.y]+1;//注意判断的位置
        q.pop();
        for(int i=0; i<4; i++)
        {
            f2.x=f1.x+nex[i][0];
            f2.y=f1.y+nex[i][1];
            if(boundary(f2.x,f2.y)&&a[f2.x][f2.y]==‘.‘&&dis[f2.x][f2.y]>dis[f1.x][f1.y]+1)
            {
                dis[f2.x][f2.y]=dis[f1.x][f1.y]+1;
                q.push(f2);
            }
        }
    }
    return 0;
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d",&n,&m);
        for(int i=0; i<n; i++)
        {
            getchar();
            for(int j=0; j<m; j++)
            {
                scanf("%c",&a[i][j]);
                if(a[i][j]==‘J‘) jx=i,jy=j;
            }
        }
        fire_bfs();
        int c=bfs();
        if(c==0) printf("IMPOSSIBLE\n");
        else printf("%d\n",c);
    }
    return 0;
}