#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define pb push_back
#define pii pair<int, int>

using namespace std;

const int M = 1e6 + 10;
int rt[M], a[M], l[M], hh[M], tt[M], L[M], tot;

struct Moore {
	int nw;
	ll cnt;
	Moore() {
		nw = -1, cnt = 0;
	}
	void insert(int x) {
		if (nw == x) cnt ++ ;
		else if (cnt > 0) cnt -- ;
		else nw = x, cnt = 1;
	}
	const Moore operator + (const Moore &b) const {
		Moore t;
		if (nw == b.nw) {
			t.nw = nw, t.cnt = cnt + b.cnt;
			return t;
		}
		if (cnt > b.cnt) {
			t.nw = nw, t.cnt = cnt - b.cnt;
		} else {
			t.nw = b.nw, t.cnt = b.cnt - cnt;
		}
		return t;
	}
};

struct Node {
	int l, r;
	Moore v;
} tr[22000000]; int total;

void pushup(int u) {
	tr[u].v = tr[tr[u].l].v + tr[tr[u].r].v;
}

int merge(int x, int y, int l, int r) {
	if (!x || !y) return x | y;
	if (l == r) {
		tr[x].v.nw = l, tr[x].v.cnt += tr[y].v.cnt;
		return x;
	}
	int mid = l + r >> 1;
	tr[x].l = merge(tr[x].l, tr[y].l, l, mid);
	tr[x].r = merge(tr[x].r, tr[y].r, mid + 1, r);
	tr[x].v = tr[tr[x].l].v + tr[tr[x].r].v;
	return x;
}

void modify(int u, int l, int r, int x, int y) {
	if (l == r) {
		tr[u].v.nw = l, tr[u].v.cnt += y;
		return;
	}
	int mid = l + r >> 1;
	if (x <= mid) {
		if (!tr[u].l) tr[u].l = ++ total;
		modify(tr[u].l, l, mid, x, y);
	} else {
		if (!tr[u].r) tr[u].r = ++ total;
		modify(tr[u].r, mid + 1, r, x, y);
	}
	pushup(u);
}

int ask(int u, int l, int r, int x) {
	if (!u) return 0;
	if (l == r) return tr[u].v.cnt;
	int mid = l + r >> 1;
	if (x <= mid) return ask(tr[u].l, l, mid, x);
	else return ask(tr[u].r, mid + 1, r, x);
}

int main() {
	int n, q;
	scanf("%d%d", &n, &q);
	total = n + q;
	for (int i = 1; i <= n + q; i ++ ) rt[i] = i;
	for (int i = 1; i <= n; i ++ ) {
		scanf("%d", &l[i]);
		for (int j = 0; j < l[i]; j ++ ) {
			++ tot;
			scanf("%d", &a[tot]);
			if (!tt[i]) {
				hh[i] = tt[i] = tot;
			} else {
				L[tot] = tt[i];
				tt[i] = tot;
			}
			modify(rt[i], 0, 1e6, a[tot], 1);
		}
	}
	while (q -- ) {
		int op;
		scanf("%d", &op);
		if (op == 1) {
			int x, y;
			scanf("%d%d", &x, &y);
			a[++ tot] = y;
			if (!l[x]) {
				hh[x] = tt[x] = tot;
			} else {
				L[tot] = tt[x], tt[x] = tot;
			}
			l[x] ++ ;
			modify(rt[x], 0, 1e6, y, 1);
		} else if (op == 2) {
			int x;
			scanf("%d", &x);
			modify(rt[x], 0, 1e6, a[tt[x]], -1);
			l[x] -- ;
			tt[x] = L[tt[x]];
		} else if (op == 3) {
			int k;
			scanf("%d", &k);
			vector<int> x(k);
			Moore t;
			for (int i = 0; i < k; i ++ ) {
				scanf("%d", &x[i]);
				t = t + tr[rt[x[i]]].v;
			}
			int num = t.nw;
			ll sum = 0, cnt = 0;
			for (int i = 0; i < k; i ++ ) {
				sum += l[x[i]];
				cnt += ask(rt[x[i]], 0, 1e6, num);
			}
			if (cnt > sum / 2) {
				printf("%d\n", num);
			} else {
				puts("-1");
			}
		} else {
			int x1, x2, x3;
			scanf("%d%d%d", &x1, &x2, &x3);
			if (!l[x1] && !l[x2]) {
				continue;
			}
			l[x3] = l[x1] + l[x2];
			l[x1] = l[x2] = 0;
			if (l[x1] && l[x2]) L[hh[x2]] = tt[x1];
			if (l[x1]) hh[x3] = hh[x1];
			else hh[x3] = hh[x2];
			if (l[x2]) tt[x3] = tt[x2];
			else tt[x3] = tt[x1];
			rt[x3] = merge(rt[x1], rt[x2], 0, 1e6);
		}
	}
	return 0;
}