#include<bits/stdc++.h>
using namespace std;
int main()
{
	ios_base::sync_with_stdio(false);
	int n,k;
	cin>>n>>k;
	vector<vector<int>> G(n+5);
	vector<int> deg(n+5);
	for(int i=1;i<n;i++)
	{
		int u,v;
		cin>>u>>v;
		G[u].push_back(v);
		G[v].push_back(u);
		deg[u]++;deg[v]++;
	}
	int need=0;
	for(int i=0;i<n;i++)
	{
		if(deg[i]!=1)need++;
	}
	vector<int> good(n+5);
	if(k<need+1)
	{
		cout<<"ATTACK"<<endl;
		//interact
		for(int i=1;i<=k;i++)
		{
			int x;
			cin>>x;
			good[x]=1;
		}
		while(1)
		{
			for(int u=0;u<n;u++)
			{
				int allbad=1;
				allbad &= !good[u];
				for(auto v:G[u])
				{
					allbad &= !good[v];
				}
				if(allbad)
				{
					cout<<u<<endl;
					return 0;
				}
			}
			vector<int> vis(n+5),siz(n+5),gsiz(n+5),pa(n+5,-1),emp(n+5,0);
			function<void(int)> dfs=[&](int u)
			{
				siz[u]=(deg[u]!=1);
				gsiz[u]=good[u];
				vis[u]=1;
				emp[u]=(deg[u]!=1 and not good[u]);
				for(auto v:G[u])
				{
					if(not vis[v])
					{
						pa[v]=u;
						dfs(v);
						siz[u]+=siz[v];
						gsiz[u]+=gsiz[v];
						emp[u]|=emp[v];
					}
				}
			};
			int found=0;
			for(int x=0;x<n;x++)
			{
				if(deg[x]!=1 and good[x]==0)
				{
					fill(pa.begin(),pa.end(),-1);
					fill(vis.begin(),vis.end(),0);
					fill(siz.begin(),siz.end(),0);
					fill(gsiz.begin(),gsiz.end(),0);
					dfs(x);
					for(int i=0;i<n;i++)
					{
						if(deg[i]==1)
						{
							int tt=i;
							while(pa[tt]!=x)
								tt=pa[tt];
							if(not emp[tt] and gsiz[tt]<=siz[tt])
							{
								cout<<i<<endl;
								found=1;
								break;
							}
						}
					}
					if(found)break;
				}
			}
			if(not found)
			{
				for(int i=0;i<n;i++)
				{
					if(deg[i]==1)
					{
						cout<<i<<endl;
						found=1;
						break;
					}
				}
			}
			assert(found);
			int chg;
			cin>>chg;
			vector<int> ngood(n+5);
			for(int i=0;i<chg;i++)
			{
				int u,v;
				cin>>u>>v;
				ngood[v]=1;
				good[u]=0;
			}
			for(int i=0;i<n;i++)
				good[i]|=ngood[i];
		}
	}
	else
	{
		cout<<"DEFEND"<<endl;
		int now=0;
		for(int i=0;i<n;i++)
		{
			if(deg[i]!=1)
			{
				cout<<i<<' ';
				good[i]=1;
				now++;
			}
		}
		for(int i=0;i<n;i++)
		{
			if(now==k)break;
			if(deg[i]==1)
			{
				cout<<i<<' ';
				good[i]=1;
				now++;
			}
		}
		cout<<endl;
		//interact
		vector<int> pa(n+5,-1);
		function<void(int)> dfs=[&](int u)
		{
			for(auto v:G[u])
			{
				if(pa[u]==v)continue;
				pa[v]=u;
				dfs(v);
			}
		};
		int x;
		while(cin>>x and x!=-1)
		{
			if(good[x]){cout<<0<<endl;}
			else
			{
				fill(pa.begin(),pa.end(),-1);
				dfs(x);
				vector<pair<int,int>> mv;
				for(int i=0;i<n;i++)
				{
					if(deg[i]==1 and good[i]==1)
					{
						int u=i;
						while(pa[u]!=-1)
						{
							mv.emplace_back(u,pa[u]);
							u=pa[u];
						}
						good[i]=0;
						good[x]=1;
						break;
					}
				}
				reverse(mv.begin(),mv.end());
				cout<<mv.size()<<endl;
				for(auto [u,v]:mv)
					cout<<u<<' '<<v<<endl;
			}
		}
	}
	
	return 0;
}