#include <iostream>

#include <cstdio>

#include <algorithm>

#include <cstring>

#include <queue>

#define LL long long

using namespace std;

const int MAX=123460;

struct Edge{

	int u,v,next;

}edge[MAX*2];

int head[MAX],dis[MAX];

int n,m,tot;

bool chose[MAX];

int pre[MAX],point[MAX],deg[MAX];

int dis1[MAX],node1[MAX],dis2[MAX],node2[MAX];

bool vis[MAX];

void addedge(int u,int v){

	edge[tot].u=u;

	edge[tot].v=v;

	edge[tot].next=head[u];

	head[u]=tot++;

}

int BFS(int rt,int counts){

	queue<int>que;

	que.push(rt);

	vis[rt]=true;

	int u,v;

	while(!que.empty()&&counts){

		u=que.front();

		que.pop();

		vis[u]=true;

		if(chose[u]) counts--;

		for(int e=head[u];e!=-1;e=edge[e].next){

			v=edge[e].v;

			if(vis[v]) continue;

			que.push(v);

			pre[v]=u;

		}

	}

	memset(vis,false,sizeof(vis));

	while(!que.empty()) que.pop();

	for(int i=1;i<=m;i++) que.push(point[i]);

	while(!que.empty()){

		u=que.front();

		que.pop();

		v=pre[u];

		if(v!=-1){

			if(!vis[v]){

				que.push(v);

				chose[v]=false;

			}

			vis[v]=true;

		}

	}

	while(!que.empty()) que.pop();

	memset(vis,false,sizeof(vis));

	for(int i=1;i<=m;i++) if(chose[point[i]]) que.push(point[i]);

	memset(deg,0,sizeof(deg));

	int ans=0;

	while(!que.empty()){

		u=que.front();

		vis[u]=true;

		que.pop();

		v=pre[u];

		if(v!=-1){

			ans++;

			if(!vis[v])

				que.push(v);

			deg[v]++;

			vis[v]=true;

		}

	}

	while(!que.empty()) que.pop();

	for(int i=1;i<=m;i++) if(chose[point[i]]) que.push(point[i]);

	while(!que.empty()){

		u=que.front();

		dis[dis1[u]]=dis[dis1[u]]==0?min(node1[u],u):min(min(node1[u],u),dis[dis1[u]]);

		dis[dis1[u]+dis2[u]]=dis[dis1[u]+dis2[u]]==0?min(node1[u],node2[u]):min(min(node1[u],node2[u]),dis[dis1[u]+dis2[u]]);

		que.pop();

		v=pre[u];

		if(v!=-1){

			deg[v]--;

			if(!deg[v]) que.push(v);

			dis1[u]+=1;

			if(dis1[u]>dis1[v]){

				dis2[v]=dis1[v],node2[v]=node1[v];

				dis1[v]=dis1[u],node1[v]=node1[u];

			}

			else if(dis1[u]==dis1[v]){

				if(node1[u]<node1[v]){

					dis2[v]=dis1[v],node2[v]=node1[v];

					node1[v]=node1[u];

				}

				else{

					if(dis1[u]>dis2[v]){

						dis2[v]=dis1[u],node2[v]=node1[u];

					}

					else if(dis1[u]==dis2[v]){

						if(node1[u]<node2[v]){

							node2[v]=node1[u];

						}

					}

				}

			}

			else{

				if(dis1[u]>dis2[v]){

					dis2[v]=dis1[u],node2[v]=node1[u];

				}

				else if(dis1[u]==dis2[v]){

					if(node1[u]<node2[v]){

						node2[v]=node1[u];

					}

				}

			}

		}

	}

///	cout<<ans<<endl;

///	printf("%d\n",node1[rt]);

	for(int i=n;i>=1;i--){

		if(dis[i]>0){

			printf("%d\n",dis[i]);

			return ans*2-i;

		}

	}

	printf("%d\n",point[1]);

	return ans;

}

int main(){

	int u,v;

	while(scanf("%d%d",&n,&m)!=EOF){

		for(int i=1;i<=n;i++){

			head[i]=-1,chose[i]=false,pre[i]=-1;

			dis1[i]=dis2[i]=0,node1[i]=node2[i]=i;

			vis[i]=false; dis[i]=0;

		}

		tot=0;

		for(int i=1;i<n;i++){

			scanf("%d%d",&u,&v);

			addedge(u,v);

			addedge(v,u);

		}

		for(int i=1;i<=m;i++){

			scanf("%d",&u);

			point[i]=u;

			chose[u]=true;

		}

		printf("%d\n",BFS(u,m));

	}

	return 0;

}