#include <iostream>
#include <cstdio>
#include <sstream>
#include <cstring>
#include <map>
#include <cctype>
#include <set>
#include <vector>
#include <stack>
#include <queue>
#include <algorithm>
#include <cmath>
#include <bitset>
#define rap(i, a, n) for(int i=a; i<=n; i++)
#define rep(i, a, n) for(int i=a; i<n; i++)
#define lap(i, a, n) for(int i=n; i>=a; i--)
#define lep(i, a, n) for(int i=n; i>a; i--)
#define rd(a) scanf("%d", &a)
#define rlld(a) scanf("%lld", &a)
#define rc(a) scanf("%c", &a)
#define rs(a) scanf("%s", a)
#define rb(a) scanf("%lf", &a)
#define rf(a) scanf("%f", &a)
#define pd(a) printf("%d\n", a)
#define plld(a) printf("%lld\n", a)
#define pc(a) printf("%c\n", a)
#define ps(a) printf("%s\n", a)
#define MOD 2018
#define LL long long
#define ULL unsigned long long
#define Pair pair<int, int>
#define mem(a, b) memset(a, b, sizeof(a))
#define _  ios_base::sync_with_stdio(0),cin.tie(0)
//freopen("1.txt", "r", stdin);
using namespace std;
const int maxn = 410000, INF = 0x7fffffff, maxm = 410000;
int n, m, s, t;
int head[maxn], cur[maxn], vis[maxn], d[maxn], cnt, nex[maxm << 1], nex2[maxm << 1];
int head2[maxn], cnt2;
int vis1[maxn], vis2[maxn];

struct node
{
    int u, v, c, flag;
}Node[maxm << 1], Edge[maxm << 1];

void add_(int u, int v, int c, int flag)
{
    Node[cnt].u = u;
    Node[cnt].v = v;
    Node[cnt].c = c;
    Node[cnt].flag = flag;
    nex[cnt] = head[u];
    head[u] = cnt++;
}

void add(int u, int v, int c)
{
    add_(u, v, c, 1);
    add_(v, u, 0, 0);
}

void add2(int u, int v)
{
    Edge[cnt2].u = u;
    Edge[cnt2].v = v;
    nex2[cnt2] = head2[u];
    head2[u] = cnt2++;
}


bool bfs()
{
    queue<int> Q;
    mem(d, 0);
    Q.push(s);
    d[s] = 1;
    while(!Q.empty())
    {
        int u = Q.front(); Q.pop();
        for(int i = head[u]; i != -1; i = nex[i])
        {
            int v = Node[i].v;
            if(!d[v] && Node[i].c > 0)
            {
                d[v] = d[u] + 1;
                Q.push(v);
                if(v == t) return 1;
            }
        }
    }
    return d[t] != 0;
}

int dfs(int u, int cap)
{
    int ret = 0;
    if(u == t || cap == 0)
        return cap;
    for(int &i = cur[u]; i != -1; i = nex[i])
    {
        int v = Node[i].v;
        if(d[v] == d[u] + 1 && Node[i].c > 0)
        {
            int V = dfs(v, min(cap, Node[i].c));
            Node[i].c -= V;
            Node[i ^ 1].c += V;
            ret += V;
            cap -= V;
            if(cap == 0) break;
        }
    }
    if(cap > 0) d[u] = -1;
    return ret;
}

int Dinic()
{
    int ans = 0;
    while(bfs())
    {
        memcpy(cur, head, sizeof head);
        ans += dfs(s, INF);
    }
    return ans;
}

int pre[maxn], low[maxn], sccno[maxn], dfs_clock, scc_cnt;
stack<int> S;

void dfs(int u)
{
    pre[u] = low[u] = ++dfs_clock;
    S.push(u);
    for(int i = head2[u]; i != -1; i = nex2[i])
    {
        int v = Edge[i].v;
        if(!pre[v])
        {
            dfs(v);
            low[u] = min(low[u], low[v]);
        }
        else if(!sccno[v])
            low[u] = min(low[u], pre[v]);
    }
    if(low[u] == pre[u])
    {
        scc_cnt++;
        for(;;)
        {
            int x = S.top(); S.pop();
            sccno[x] = scc_cnt;
            if(x == u) break;
        }
    }
}
int G[maxn], ans;
int main()
{
    int T;
    int kase = 0;
    rd(T);
    while(T--)
    {
        mem(head, -1), mem(head2, -1);
        mem(vis1, 0), mem(vis2, 0);
        cnt = cnt2 = 0;
        rd(n), rd(m);
        s = 0, t = maxn - 1;
        bool flag = 0;
        int tmp, u, v;
        int x = max(n, m);
        for(int i = 1; i <= n; i++)
        {
            add(s, i, 1);
            rd(tmp);
            for(int j = 1; j <= tmp; j++)
            {
                rd(v);
                add(i, x + v, 1);
                add2(i, x + v);
            }
        }
        for(int i = 1; i <= m; i++) add(x + i, t, 1);
        int max_cnt = Dinic();

        int mx = x * 2;
        for(int i = 1; i <= m - max_cnt; i++)
        {
            mx++;
            add(s, mx, 1);
            for(int j = 1; j <= m; j++)
                add(mx, x + j, 1), add2(mx, x + j);
        }
        for(int i = 1; i <= n - max_cnt; i++)
        {
            mx++;
            add(mx, t, 1);
            for(int j = 1; j <= n; j++)
                add(j, mx, 1), add2(j, mx);
        }
        Dinic();
        for(int i = 0; i < cnt; i++)
        {
            if(!Node[i].flag || Node[i].u == s || Node[i].v == t || Node[i].c != 0) continue;
            add2(Node[i].v, Node[i].u);
        }
        dfs_clock = scc_cnt = 0;
        mem(sccno, 0);
        mem(pre, 0);
        for(int i = 1; i <= mx; i++)
            if(!pre[i]) dfs(i);
        printf("Case #%d:\n", ++kase);
        for(int i = 1; i <= n; i++)
        {
            ans = 0;
            for(int j = head2[i]; j != -1; j = nex2[j])
            {
                int v = Edge[j].v;
                if(sccno[i] == sccno[v] && v - x <= m)
                    G[ans++] = v;
            }
            sort(G, G + ans);
            printf("%d", ans);
            for(int j = 0; j < ans; j++)
            {
                printf(" ");
                printf("%d", G[j] - x);
            }

           printf("\n");

        }

    }

    return 0;
}