#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <iostream>
#include <cstdio>
#include <string.h>
#include <algorithm>
#include <cmath>
#include <vector>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <map>
#include <ctype.h>
#include <time.h>#define abs(x) ((x)>=0?(x):-(x))
#define i64 long long
#define u32 unsigned int
#define u64 unsigned long long
#define clr(x,y) memset(x,y,sizeof(x))
#define CLR(x) x.clear()
#define ph(x) push(x)
#define pb(x) push_back(x)
#define Len(x) x.length()
#define SZ(x) x.size()
#define PI acos(-1.0)
#define sqr(x) ((x)*(x))
#define MP(x,y) make_pair(x,y)
#define EPS 1e-10#define FOR0(i,x) for(i=0;i<x;i++)
#define FOR1(i,x) for(i=1;i<=x;i++)
#define FOR(i,a,b) for(i=a;i<=b;i++)
#define FORL0(i,a) for(i=a;i>=0;i--)
#define FORL1(i,a) for(i=a;i>=1;i--)
#define FORL(i,a,b)for(i=a;i>=b;i--)#define rush() int CC;for(scanf("%d",&CC);CC--;)
#define Rush(n)  while(scanf("%d",&n)!=-1)
using namespace std;void RD(int &x){scanf("%d",&x);}
void RD(i64 &x){scanf("%I64d",&x);}
void RD(u64 &x){scanf("%I64u",&x);}
void RD(u32 &x){scanf("%u",&x);}
void RD(double &x){scanf("%lf",&x);}
void RD(int &x,int &y){scanf("%d%d",&x,&y);}
void RD(i64 &x,i64 &y){scanf("%lld%lld",&x,&y);}
void RD(u32 &x,u32 &y){scanf("%u%u",&x,&y);}
void RD(double &x,double &y){scanf("%lf%lf",&x,&y);}
void RD(double &x,double &y,double &z){scanf("%lf%lf%lf",&x,&y,&z);}
void RD(int &x,int &y,int &z){scanf("%d%d%d",&x,&y,&z);}
void RD(i64 &x,i64 &y,i64 &z){scanf("%lld%lld%lld",&x,&y,&z);}
void RD(u32 &x,u32 &y,u32 &z){scanf("%u%u%u",&x,&y,&z);}
void RD(char &x){x=getchar();}
void RD(char *s){scanf("%s",s);}
void RD(string &s){cin>>s;}void PR(int x) {printf("%d\n",x);}
void PR(int x,int y) {printf("%d %d\n",x,y);}
void PR(i64 x) {printf("%lld\n",x);}
void PR(i64 x,i64 y) {printf("%lld %lld\n",x,y);}
void PR(u32 x) {printf("%u\n",x);}
void PR(u64 x) {printf("%llu\n",x);}
void PR(double x) {printf("%.3lf\n",x);}
void PR(double x,double y) {printf("%.5lf %.5lf\n",x,y);}
void PR(char x) {printf("%c\n",x);}
void PR(char *x) {printf("%s\n",x);}
void PR(string x) {cout<<x<<endl;}void upMin(int &x,int y) {if(x>y) x=y;}
void upMin(i64 &x,i64 y) {if(x>y) x=y;}
void upMin(double &x,double y) {if(x>y) x=y;}
void upMax(int &x,int y) {if(x<y) x=y;}
void upMax(i64 &x,i64 y) {if(x<y) x=y;}
void upMax(double &x,double y) {if(x<y) x=y;}const int mod=1000000007;
const i64 inf=((i64)1)<<60;
const double dinf=1000000000000000000.0;
const int INF=100000000;
const int N=1005;vector<int> g[N],ans[N];int dfn[N],low[N],visit[N],num,id,color[N];
stack<int> S;int n,m;
int G[N][N];
int match[N],X,p[N];
int M;int DFS(int u)
{int i;FOR1(i,M) if(G[u][i]&&X!=visit[i]){visit[i]=X;if(match[i]==-1||DFS(match[i])){match[i]=u;p[u]=i;return 1;}}return 0;
}void dfs(int u)
{dfn[u]=low[u]=++id;S.push(u);int i,v;FOR0(i,SZ(g[u])){v=g[u][i];if(!dfn[v]){dfs(v);upMin(low[u],low[v]);}else if(X!=visit[v]){upMin(low[u],dfn[v]);}}if(low[u]==dfn[u]){num++;do{v=S.top();S.pop();visit[v]=X;color[v]=num;}while(u!=v);}
}int main()
{int Num=0;rush(){RD(n,m);int i,j,k,x;clr(G,0);FOR1(i,n){RD(k);while(k--) RD(x),G[i][x]=1;}    clr(match,-1); clr(p,-1);int cnt=0;M=m;FOR1(i,n) X++,cnt+=DFS(i);M=n+m-cnt;for(i=n+1;i<=M;i++) FOR1(j,M) G[i][j]=1;for(i=m+1;i<=M;i++) FOR1(j,M) G[j][i]=1;clr(match,-1); clr(p,-1);FOR1(i,M) X++,DFS(i);FOR1(i,M) g[i].clear(),ans[i].clear();FOR1(i,M) {FOR1(j,M) if(p[i]!=j&&G[i][j]) {g[p[i]].pb(j);}}clr(dfn,0); X++; id=num=0;FOR1(i,M) if(!dfn[i]) dfs(i);FOR1(i,n) FOR1(j,m) if(G[i][j]&&color[j]==color[p[i]]){ans[i].pb(j);}printf("Case #%d:\n",++Num);FOR1(i,n) {printf("%d",(int)SZ(ans[i]));FOR0(k,SZ(ans[i])) printf(" %d",ans[i][k]);puts("");}}
}