#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];
vector<int>now;
map<int,vector<int>>ans;
vector<int>t1,t2;
int tot=0;
int nn;

void dfs(int v,int pre,int dd){
    vis[v]=1;
    now.pb(v);
    tot++;
    for(int ii:node[v]){
        if(!vis[ii]){
            dfs(ii,v,dd+1);
        }
        else if(ii==nn){
            if(ans.count(dd)){
                t1=ans[dd];
                t2=now;
                vector<int>t3=t2;
                reverse(t3.begin()+1,t3.end());
                if(t3==t1) {
                    t1.clear(),t2.clear();
                    continue;
                }
                return;
            }
            else ans[dd]=now;
        }
        if(t1.size()) return;
    }
    now.pop_back();
    vis[v]=0;
}

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++){
        nn=i;
        dfs(i,i,0);   
        if(t1.size()){
            cout<<t1.size()<<"\n";
            for(int ii:t1) cout<<ii<<" ";cout<<"\n";
            for(int ii:t2) cout<<ii<<" ";cout<<"\n";
            return;
        }
        ans.clear();
    }

}

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