#include <bits/stdc++.h>
using std::bitset;
using std::cout;
using std::deque;
using std::endl;
using std::greater;
using std::lower_bound;
using std::make_pair;
using std::map;
using std::max;
using std::min;
using std::multimap;
using std::multiset;
using std::nth_element;
using std::pair;
using std::priority_queue;
using std::queue;
using std::reverse; 
using std::set;
using std::sort;
using std::sqrt;
using std::stable_sort;
using std::string;
using std::swap;
using std::unique;
using std::upper_bound;
using std::vector;
typedef long long li;
typedef long double lf; 

inline li read(){
	li ans = 0, f = 1;
	char ch = getchar();
	while(ch < '0' || ch > '9'){
		f = (ch == '-') ? -1 : 1;
		ch = getchar();
	}
	while(ch <= '9' && ch >= '0'){
		ans = ans * 10 + (ch ^ 48);
		ch = getchar();
	}
	return ans * f;
} 

li n, need;
bool win[110][110];
li f[110], a[110];
li next[110], pre[110], vis[110];
li fl;

void dfs(li u, li now){
    if(u > n){
        if(now == need){
            fl = 1;
            for(li i = 1; i <= n; i++) printf("%lld ", a[i] - 1); printf("\n");
            // cout << now << endl;
            // for(li i = 1; i <= n; i++) cout << a[i] << " "; cout << endl;
        }
        return;
    }
    if(vis[need] && now != need) return;
    for(li i = next[0]; i <= n; i = next[i]){
        if(i == need && u <= n - 13) continue;
        vis[i] = 1;
        a[u] = i;
        next[pre[i]] = next[i];
        pre[next[i]] = pre[i];
        if(win[now][i]) dfs(u + 1, now);
        else dfs(u + 1, i);
        if(fl) return;
        next[pre[i]] = i;
        pre[next[i]] = i;
        vis[i] = 0;
    }
}

queue<li> q;
li wins[200010];

int main(){
    // freopen("wonderful.ans", "r", stdin);
    // freopen("www.ww", "w", stdout); 
	li T = read();
    for(li k = 1; k <= T; k++){
        fl = 0;
        n = read(), need = read() + 1;
        wins[need] = 0;
        for(li i = 1; i <= n; i++){
            for(li j = 1; j <= n; j++){
                char ch = getchar();
                while(ch != '-' && ch != 'Y' && ch != 'N') ch = getchar();
                if(ch == 'Y') win[i][j] = 1, wins[i]++;
                else win[i][j] = 0;
            }
        }
        for(li i = 0; i <= n + 1; i++){
            pre[i] = i - 1, next[i] = i + 1;
            vis[i] = 0;
        }
        while(q.size()) q.pop();
        q.push(need);
        li cnt = 0;
        vis[need] = 1;
        while(!q.empty()){
            li k = q.front(); cnt++; q.pop();
            for(li i = 1; i <= n; i++) if(win[k][i] && !vis[i]){
                vis[i] = 1;
                q.push(i);
            }
        }
        // cout << cnt << endl;
        for(li i = 1; i <= n; i++) vis[i] = 0;
        // cout << win[35][36] << endl;
        printf("Case #%lld: ", k);
        if(cnt == n){
            if(wins[need] == 1){
                printf("%lld %lld ", n - 2, n - 1);
                for(li i = n - 2; i >= 1; i--) printf("%lld ", i - 1);
                printf("\n");
                fl = 1;
            }
             else dfs(1, 0);
        }
        if(fl){
            ;
        } else{
            puts("IMPOSSIBLE");
        }
    }
    return 0;
}