#include <bits/stdc++.h>
using namespace std;

#define int long long


typedef array<list<pair<int,int>>,3> grid;

int32_t main(){
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	int n,m;
	cin >> n >> m;
	vector<int> has_Rest(n+1);
	vector<int> has_Past(n+1);
	vector<vector<int>> adj(n+1);
	for(int i=1;i<=m;i++){
		int a;cin>>a;
		has_Rest[a]=i;
	}
	for(int i=1;i<=m;i++){
		int a;cin>>a;
		has_Past[a]=i;
	}
	for(int i=1;i<n;i++){
		int a,b;cin>>a>>b;
		adj[a].emplace_back(b);
		adj[b].emplace_back(a);
	}
	vector<int> next(2*m+1);
	auto combine = [&](pair<int,int> &a,pair<int,int> &b){
		next[a.second] = b.first;
		return a = {a.first,b.second};
	};
	int ans = 0;
	function<tuple<int,int,grid>(int,int)> dfs = [&](int x,int p)->tuple<int,int,grid>{
		int cntRest = 0;
		int cntPast = 0;
		auto add = [](list<pair<int,int>> &a,list<pair<int,int>> &b){
			if(b.size()>a.size())swap(a,b);
			for(auto&i:b)a.push_back(i);
		};
		grid curr;
		if(has_Rest[x]){
			cntRest++;
			curr[0].emplace_back(has_Rest[x],has_Rest[x]);
		}
		if(has_Past[x]){
			cntPast++;
			curr[1].emplace_back(has_Past[x]+m,has_Past[x]+m);
		}
		for(int&j:adj[x])if(j!=p){
			auto [a,b,c] = dfs(j,x);
			cntRest+=a;
			cntPast+=b;
			add(curr[0],c[0]);
			add(curr[1],c[1]);
			add(curr[2],c[2]);
		}
		if(cntPast==0 and cntRest==0)return {0,0,curr};
		if(cntPast>cntRest){
			while(!curr[2].empty()){
				curr[1].front() = combine(curr[1].front(),curr[2].front());
				curr[2].pop_front();
			}
			while(!curr[0].empty()){
				pair<int,int> a = curr[1].front();curr[1].pop_front();
				pair<int,int> b = curr[0].front();curr[0].pop_front();
				pair<int,int> c = combine(a,b);
				curr[1].front() = combine(c,curr[1].front());
			}
			grid currn;
			swap(currn[1],curr[1]);
			ans+=currn[1].size()*2;
			return {cntRest,cntPast,currn};
		}
		if(cntRest>cntPast){
			while(!curr[2].empty()){
				curr[0].front() = combine(curr[2].front(),curr[0].front());
				curr[2].pop_front();
			}
			while(!curr[1].empty()){
				pair<int,int> a = curr[1].front();curr[1].pop_front();
				pair<int,int> b = curr[0].front();curr[0].pop_front();
				pair<int,int> c = combine(b,a);
				curr[0].front() = combine(c,curr[0].front());
			}
			grid currn;
			swap(currn[0],curr[0]);
			ans+=currn[0].size()*2;
			return {cntRest,cntPast,currn};
		}
		while(!curr[0].empty()){
			pair<int,int> a = curr[0].front();curr[0].pop_front();
			pair<int,int> b = curr[1].front();curr[1].pop_front();
			a = combine(a,b);
			if(curr[0].empty())curr[2].emplace_back(a);
			else curr[0].front()=combine(a,curr[0].front());
		}
		while(curr[2].size()>1){
			pair<int,int> a = curr[2].front();curr[2].pop_front();
			curr[2].front()=combine(curr[2].front(),a);
		}
		grid currn;
		swap(currn[2],curr[2]);
		ans+=2;
		return {cntRest,cntPast,currn};
	};
	auto [a,b,c] = dfs(1,0);
	ans-=2;
	cout << ans << '\n';
	function<void(int)> ddfs = [&](int x){
		cout << (x-1)%m + 1 << ' ';
		if(c[2].front().second==x)return;
		ddfs(next[x]);
	};
	ddfs(c[2].front().first);
	cout << '\n';
}