#include<set>
#include<map>
#include<queue>
#include<vector>
#include<algorithm>
#include<bits/stdc++.h>
#define pr pair
#define f first
#define s second
#define ll long long
#define mp make_pair
#define pll pr<ll,ll>
#define pii pr<int,int>
#define piii pr<int,pii>
using namespace std;
int rt;
int ls[8003],rs[8003];
int fa[8003];
int md[8003];
int cv[8003];
void upd(int x)
{
	if(ls[x]>=0&&rs[x]>=0)
	{
		md[x]=min(md[ls[x]],md[rs[x]])+1;
		if(cv[ls[x]]>cv[rs[x]]) swap(ls[x],rs[x]);
	}
	else
	{
		md[x]=0;
		if(rs[x]>=0) swap(ls[x],rs[x]);
	}
	if(ls[x]>=0) fa[ls[x]]=x;
	if(rs[x]>=0) fa[rs[x]]=x;
}
void upm(int x)
{
	if(x==-1) return;
	if(ls[x]>=0&&rs[x]>=0) md[x]=min(md[ls[x]],md[rs[x]])+1;
	else md[x]=0;
	upm(fa[x]);
}
int main()
{
	ios_base::sync_with_stdio(0);
	int n;
	cin>>n;
	rt=-1;
	string tp;
	int x;
	n*=2;
	int cs=0;
	while(n--)
	{
		cin>>tp>>x;
		x--;
		if(tp=="add")
		{
			cs++;
			ls[x]=-1;
			rs[x]=-1;
			if(rt==-1)
			{
				cout<<0<<endl;
				cout.flush();
				rt=x;
			}
			else
			{
			vector<int> v;
			v.push_back(rt);
			v.push_back(x);
			vector<int> g;
			int j;
			for(j=rt;rs[j]!=-1;)
			{
				v.push_back(ls[j]);
				v.push_back(rs[j]);
				g.push_back(j);
				if(md[ls[j]]<=md[rs[j]]) j=ls[j];
				else j=rs[j];
			}
			if(ls[j]>=0) v.push_back(ls[j]);
			g.push_back(j);
			cout<<v.size();
			for(int i:v) cout<<' '<<i+1;
			cout<<endl;
			cout.flush();
			for(int i=0;i<v.size();i++)
			{
				int o;
				cin>>o;
				o--;
				cv[o]=i;
			}
			rs[j]=x;
			int i;
			for(i=g.size()-1;i>=0;i--)
			{
				if(cv[g[i]]<cv[x]) break;
				int s=g[i];
				if(i>0)
				{
					if(ls[g[i-1]]==s) ls[g[i-1]]=x;
					else rs[g[i-1]]=x;
				}
				else rt=x;
				swap(ls[x],ls[s]);
				swap(rs[x],rs[s]);
				if(ls[x]==x) ls[x]=s;
				else rs[x]=s;
				upd(s);
			}
			upd(x);
			for(;i>=0;i--) upd(g[i]);
			}
			fa[rt]=-1;
		}
		else
		{
			cs--;
			if(cs==0)
			{
				cout<<0<<endl;
				cout.flush();
				rt=-1;
			}
			else
			{
			vector<int> v;
			vector<int> g;
			int j;
			int rf=fa[x];
			if(rf!=-1)
			{
				if(ls[rf]==x&&rs[rf]!=-1) v.push_back(rs[rf]);
				if(rs[rf]==x&&ls[rf]!=-1) v.push_back(ls[rf]);
			}
			for(j=x;ls[j]!=-1;j=ls[j])
			{
				v.push_back(ls[j]);
				if(rs[j]>=0) v.push_back(rs[j]);
				g.push_back(ls[j]);
			}
			cout<<v.size();
			for(int i:v) cout<<' '<<i+1;
			cout<<endl;
			cout.flush();
			for(int i=0;i<v.size();i++)
			{
				int o;
				cin>>o;
				o--;
				cv[o]=i;
			}
			for(int i=0;i<g.size();i++)
			{
				int s=g[i];
				if(fa[x]!=-1)
				{
					if(ls[fa[x]]==x) ls[fa[x]]=s;
					else rs[fa[x]]=s;
				}
				else rt=s;
				fa[s]=fa[x];
				fa[x]=s;
				ls[x]=ls[s];
				ls[s]=x;
				swap(rs[x],rs[s]);
			}
			if(ls[fa[x]]==x) ls[fa[x]]=-1;
			else rs[fa[x]]=-1;
			for(int i=((int)g.size())-1;i>=0;i--) upd(g[i]);
			if(rf>=0) upd(rf);
			if(g.size()) upm(fa[g[0]]);
			else upm(rf);
			fa[rt]=-1;
			}
		}
		if(rt==-1) cout<<"-1"<<endl;
		else cout<<rt+1<<endl;
		cout.flush();
	}
	return 0;
}