#include <iostream>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <unordered_map>
#include <deque>
#include <bits/extc++.h>
#include <ctime>
#include <cstdlib>
#include <random>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;

const int N = 1e6 + 5;

mt19937 rd(114);

struct Node
{
	deque<int> q;
	gp_hash_table<int, int> mp;
}p[N];

int n, m, rp[N];

int main()
{
	//freopen("major4.in", "r", stdin);
//	freopen("1.out", "w", stdout);
	scanf("%d%d", &n, &m);
	for (int i = 1; i <= n; i++)
	{
		int cnt;
		scanf("%d", &cnt);
		while (cnt--)
		{
			int x;
			scanf("%d", &x);
			p[i].q.push_back(x);
			p[i].mp[x]++;
		}
	}
	for (int i = 0; i < N; i++) rp[i] = i;
	while (m--)
	{
		int op;
		scanf("%d", &op);
		if (op == 1)
		{
			int x, y;
			scanf("%d%d", &x, &y);
			x = rp[x];
			p[x].q.push_back(y);
			p[x].mp[y]++;
		}
		else if (op == 2)
		{
			int x;
			scanf("%d", &x);
			x = rp[x];
			p[x].mp[p[x].q.back()]--;
			p[x].q.pop_back();
		}
		else if (op == 3)
		{
			int x;
			scanf("%d", &x);
			vector<int> pe;
			int sum = 0;
			for (int i = 1; i <= x; i++)
			{
				int g;
				scanf("%d", &g);
				g = rp[g];
				sum += p[g].q.size();
				pe.push_back(g);
			}
			bool f = false;
			for (int i = 1; i <= 34; i++)
			{
				int c1 = rd() % x;
				if (p[pe[c1]].q.empty()) continue;
				int c2 = *(((rd() % p[pe[c1]].q.size()) + p[pe[c1]].q.begin()));
				int sp = 0;
				for (int j = 0; j < x; j++) sp += p[pe[j]].mp[c2];
				if (sp > sum / 2)
				{
					f = true;
					printf("%d\n", c2);
					break;
				}
			}
			if (!f) printf("-1\n");
		}
		else
		{
			int x, y, z;
			scanf("%d%d%d", &x, &y, &z);
			x = rp[x], y = rp[y];
			if (p[y].q.size() < p[x].q.size())
			{
				for (auto i : p[y].q)
				{
					p[x].q.push_back(i);
					p[x].mp[i]++;
				}
				p[y].q.clear(), p[y].q.shrink_to_fit();
				rp[z] = x;
			}
			else
			{
				while (p[x].q.size())
				{
					int i = p[x].q.back();
					p[x].q.pop_back();
					p[y].q.push_front(i);
					p[y].mp[i]++;
				}
				p[x].q.shrink_to_fit();
				rp[z] = y;
			}
		}
	}
	return 0;
}

启发式合并+deque，后面四个点t了，感觉复杂度没假吧，大样例很快啊