#include<bits/stdc++.h>

#define ll long long
#define mk make_pair
#define fi first
#define se second

using namespace std;

inline int read(){
	int x=0,f=1;char c=getchar();
	for(;(c<'0'||c>'9');c=getchar()){if(c=='-')f=-1;}
	for(;(c>='0'&&c<='9');c=getchar())x=x*10+(c&15);
	return x*f;
}

const int mod=998244353;
int ksm(int x,ll y,int p=mod){
	int ans=1;y%=(p-1);
	for(int i=y;i;i>>=1,x=1ll*x*x%p)if(i&1)ans=1ll*ans*x%p;
	return ans%p;
}
int inv(int x,int p=mod){return ksm(x,p-2,p)%p;}
mt19937 rnd(time(0));
int randint(int l,int r){return rnd()%(r-l+1)+l;}
void add(int &x,int v){x+=v;if(x>=mod)x-=mod;}
void Mod(int &x){if(x>=mod)x-=mod;}
int cmod(int x){if(x>=mod)x-=mod;return x;}

template<typename T>void cmax(T &x,T v){x=max(x,v);}
template<typename T>void cmin(T &x,T v){x=min(x,v);}

const int N=105;
bitset<N>F[N],V;
int n,Case;
bool G[N][N];

void clr(){
	for(int i=1;i<=n;i++)F[i].reset();
}

void solve(){
	n=read();int A=read()+1;
	for(int i=1;i<=n;i++)for(int j=1;j<=n;j++){
		char c=getchar();while(c!='Y'&&c!='N'&&c!='-')c=getchar();
		G[i][j]=(c=='N'),F[i][j]=(c=='Y');
	}
	for(int i=1;i<=n;i++)G[0][i]=true;

	vector<int>vis(n+1,0),ans(n+1,0);

	int now=0;
	auto chk=[&](){
		// cout<<"chk now = "<<now<<endl;
		for(int i=1;i<=n;i++)V[i]=(!vis[i]);
		queue<int>q;
		if(V[A])q.push(A),V[A]=0;
		while(q.size()){
			int x=q.front();q.pop();
			auto W=(V&F[x]);
			// cout<<"x = "<<x<<endl;
			// cout<<"W = ";for(int i=1;i<=n;i++)cout<<W[i];puts("");
			int cc=W.count();
			for(int _=1;_<=cc;_++){
				int x=W._Find_first();
				q.push(x),V[x]=0,W[x]=0;
			}
		}
		for(int i=1;i<=n;i++)if(V[i]){
			if(!G[i][now])return false;
		}
		return true;
	};

	if(!chk()){
		cout<<"Case #"<<++Case<<": IMPOSSIBLE\n";
		clr();return ;
	}

	for(int i=1;i<=n;i++){
		int tmp=now;
		for(int j=1;j<=n;j++)if(!vis[j]){
			vis[j]=true,now=(G[now][j]?j:now);
			if(chk()){ans[i]=j;break;}
			vis[j]=false,now=tmp;
		}
		now=(G[now][ans[i]]?ans[i]:now);
	}

	cout<<"Case #"<<++Case<<": ";
	for(int i=1;i<=n;i++)cout<<ans[i]-1<<" \n"[i==n];
	clr();
}

signed main(void){

#ifndef ONLINE_JUDGE
	// freopen("a.in","r",stdin);
	// freopen("a.out","w",stdout);
	// freopen("sort/ex_1.in","r",stdin);
	// freopen("in.txt","r",stdin);
#endif

	int tt=read();while(tt--)solve();

	return 0;
}