/*
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
 */
#include<bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
 
//using namespace __gnu_pbds;
using namespace std;
 
typedef long double ld;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int>vi;
typedef vector<vector<int>>vvi;
typedef vector<ll>vl;
typedef vector<vl> vvl;
typedef pair<int,int>pi;
typedef pair<ll,ll> pl;
typedef vector<pl> vpl;
typedef vector<ld> vld;
typedef pair<ld,ld> pld;
typedef vector<pi> vpi;
 
//typedef tree<ll, null_type, less_equal<ll>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
template<typename T> ostream& operator<<(ostream& os, vector<T>& a){os<<"[";for(int i=0; i<ll(a.size()); i++){os << a[i] << ((i!=ll(a.size()-1)?" ":""));}os << "]\n"; return os;}
 
#define all(x) x.begin(),x.end()
#define YES out("YES")
#define NO out("NO")
#define out(x){cout << x << "\n"; return;}
#define outfl(x){cout << x << endl;return;}
#define GLHF ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define print(x){for(auto ait:x) cout << ait << " "; cout << "\n";}
#define pb push_back
#define umap unordered_map
 
template<typename T1, typename T2> istream& operator>>(istream& is, pair<T1, T2>& p){is >> p.first >> p.second;return is;}
template<typename T1, typename T2> ostream& operator<<(ostream& os, pair<T1, T2>& p){os <<"" << p.first << " " << p.second << ""; return os;}
void usaco(string taskname){
    string fin = taskname + ".in";
    string fout = taskname + ".out";
    const char* FIN = fin.c_str();
    const char* FOUT = fout.c_str();
    freopen(FIN, "r", stdin);
    freopen(FOUT, "w", stdout);
}
template<typename T>
void read(vector<T>& v){
    int n=v.size();
    for(int i=0; i<n; i++)
        cin >> v[i];
}
template<typename T>
vector<T>UNQ(vector<T>a){
    vector<T>ans;
    for(T t:a)
        if(ans.empty() || t!=ans.back())
            ans.push_back(t);
    return ans;
}
 
 
 
#include "speedrun.h"
 
vvi g;
vi ord;
void set1(int i,int x){
    for(int j=0; j<10; j++)
        if(x&(1<<j))
            setHint(i,j+1,1);
}
void set2(int i,int x){
    for(int j=0; j<10; j++)
        if(x&(1<<j))
            setHint(i,j+10+1,1);
}
 
void dfsp(int src,int par){
    if(par!=-1)
        set2(src,par);
    ord.pb(src);
    for(int nbr:g[src])
        if(nbr!=par)
            dfsp(nbr,src);
}
void assignHints(int subtask, int n, int A[], int B[]) {
    g.resize(n+1);
    for(int i=1; i<n; i++){
        g[A[i]].pb(B[i]);
        g[B[i]].pb(A[i]);
    }
 
    setHintLen(21);
    dfsp(1,-1);
 
    set2(1,ord.back());
    for(int i=0; i<n; i++){
        set1(ord[i],ord[(i+1)%ord.size()]);
    }
    for(int i=2; i<=n; i++)
        setHint(i,21,g[i].size()==1);
}
 
int get(int ix){
    int ans=0;
    for(int i=0; i<10; i++)
        if(getHint(1+i+10*ix))
            ans+=(1<<i);
    return ans;
}
 
stack<int>nxt;
vector<bool>vis;
void dfs(int src,int par){
    int cnxt=get(0),cprv=get(1);
    vis[src]=1;
    if(getHint(21) && !vis[cnxt])
        nxt.push(cnxt);
 
    while(!getHint(21)){
        bool ok=0;
        while(nxt.size() && !vis[nxt.top()] && goTo(nxt.top())){
            int t=nxt.top();
            nxt.pop();
            dfs(t,src);
            ok=1;
        }
        if(!vis[cnxt] && goTo(cnxt)) {
            dfs(cnxt, src);
            if(!nxt.size())
                break;
            cnxt=nxt.top();
            ok=1;
        }
        if(!ok)break;
    }
    if(!vis[cprv] && goTo(cprv))
        dfs(cprv,src);
    if(par!=-1)
        goTo(par);
}
 
void speedrun(int subtask, int N, int start) {
    vis.resize(N+1);
    dfs(start,-1);
    bool ok=1;
}
/*
5
1 2
1 3
3 4
3 5
 
5
1 2
1 3
1 4
1 5
 
7
1 2
1 3
2 4
2 5
3 6
3 7
 
18
1 2
1 3
2 4
2 5
3 6
3 7
5 8
6 9
6 10
1 11
3 12
12 13
8 14
14 15
15 16
16 17
1 18
 */