#include<bits/stdc++.h>

using namespace std;

#define F first 
#define S second 
#define pb push_back
#define int long long

vector<int>node[100005];
bool vis[100005];
int dep[100005],pp[100005];
int id[100005],pid[100005];
pair<int,int>ans[100005];
int now=0,t1,t2;
int iu=0;
int dfn[100005];

void dfs(int v,int pre){
    // cerr<<v<<"\n";
    dfn[v]=++iu;
    pp[v]=pre;
    dep[v]=dep[pre]+1;
    vis[v]=1;
    for(int ii:node[v]){
        if(ii==pre) continue;
        if(!vis[ii]){
            dfs(ii,v);
        }
        else if(dfn[v]>dfn[ii]){
            int dd=dep[v]-dep[ii];
            int g1=v,g2=ii;
            dd=abs(dd);
            if(id[dd]){
                now=dd;t1=g1,t2=g2;
            }
            else ans[dd].F=g1,ans[dd].S=g2;
            id[dd]=g1;pid[dd]=g2;
        }
    }
}

void solve(){
    int n;
    cin>>n;
    for(int i=1;i<=n*2-3;i++){
        int g,h;
        cin>>g>>h;
        node[g].pb(h);
        node[h].pb(g);
    }
    for(int i=1;i<=n;i++){
        if(!vis[i]) dfs(i,i);
    }

    bool nn=0;
    if(!now) {
        now=2;
        nn=1;
        t1=id[n-2],t2=id[n-1];
        // for(int i=2;i<=n;i++) cerr<<id[i]<<" ";cerr<<"\n";
        // return;
    }
    // cerr<<now<<"\n"<<ans[now].F<<" "<<ans[now].S<<" "<<t1<<" "<<t2<<"\n";
    // return;
    

    int g1=ans[now].F,h1=ans[now].S;
    swap(g1,h1);swap(t1,t2);
    // cerr<<now<<"\n";
    cout<<now+1<<"\n";
    while(h1!=g1) cout<<h1<<" ",h1=pp[h1];
    cout<<g1<<"\n";

    if(nn){
        if(t1==t2) {
            if(pid[n-2]!=1) t1=pid[n-2];
            else t2=pid[n-1];
        }
        cout<<t1<<" "<<1<<" "<<t2<<"\n";
        return;
    }

    while(t2!=t1) cout<<t2<<" ",t2=pp[t2];
    cout<<t1<<"\n";
}

signed main(){
    ios::sync_with_stdio(0);cin.tie(0);
    solve();
    return 0;
}