#include"cstdio"

#include"queue"

#include"cstring"

using namespace std;

const int MAXN=;

const int INF=0X7fffffff;

typedef pair<int,int> P;

char mp[MAXN][MAXN];

int ft[MAXN][MAXN];

int jt[MAXN][MAXN];

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

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

int n,m;

int sy,sx;

void bfs1()//第一次广搜确定 fire到达passable square的时间

{

    queue<P> que;

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

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

        {

            ft[i][j]=INF;

            if(mp[i][j]=='F')

            {

                que.push(P(i,j));

                ft[i][j]=;

            }

        }

    while(!que.empty())

    {

        P now = que.front();que.pop();

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

        {

            int ny=now.first+dy[i];

            int nx=now.second+dx[i];

            if(<=ny&&ny<n&&<=nx&&nx<m&&mp[ny][nx]!='#')

            {

                int dist=ft[now.first][now.second]+;

                if(dist<ft[ny][nx])

                {

                    ft[ny][nx]=dist;

                    que.push(P(ny,nx));

                }

            }

        }

    }

}

void bfs2()

{

    memset(jt,-,sizeof(jt));

    queue<P> que;

    que.push(P(sy,sx));

    jt[sy][sx]=;

    while(!que.empty())

    {

        P now=que.front();que.pop();

        if(now.first==||now.first==n-||now.second==||now.second==m-)

        {

            printf("%d\n",jt[now.first][now.second]+);//逃出迷宫,注意+1

            return ;

        }

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

        {

            int ny=now.first+dy[i];

            int nx=now.second+dx[i];

            if(<=ny&&ny<n&&<=nx&&nx<m&&mp[ny][nx]!='#'&&jt[ny][nx]==-)

            {

                int dist=jt[now.first][now.second]+;

                if(dist<ft[ny][nx])//若在该时刻该点没有火焰到达说明可行

                {

                    jt[ny][nx]=dist;

                    que.push(P(ny,nx));

                }

            }

        }

    }

    printf("IMPOSSIBLE\n");

}

int main()

{

    int t;

    scanf("%d",&t);

    while(t--)

    {

        scanf("%d%d",&n,&m);

        scanf("%*c");

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

        {

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

            {

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

                if(mp[i][j]=='J')

                {

                    sy=i,sx=j;

                }

            }

            scanf("%*c");

        }

        bfs1();

        bfs2();

    }

    return ;

}