#include <bits/stdc++.h>

using namespace std;

#define int long long
#define ll long long
#define forn(i, n) for (ll i = 0; i < n; ++i)
#define forr(i, s, n) for (ll i = s; i < n; ++i)
#define fori(i, s, n) for (ll i = s; i > n; --i)
#define fora(i, n) for (auto i: n)
#define vi vector<int>
#define vll vector<ll>
#define prints(n) cout << (n) << " "
#define println(n) cout << (n) << "\n"

const int MOD = 998244353;
// const int MOD = 1e9 + 7;
vector<vi> adj;

vi dep;
vi par;
vector<vi> spt;
vi vis;

vector<pair<int, int>> vp;
vector<vector<pair<int, int>>> cy;


void dfs(int u, int p=0, int d=0) {
    // cout << u + 1 << ' ' << p + 1 << ' ' << d << '\n';
    if (vis[u]) {
        vp.emplace_back(u, p);
        return;
    }
    dep[u] = d;
    par[u] = p;
    vis[u] = 1;
    for (int v: adj[u]) {
        if (v == p) continue;
        dfs(v, u, d + 1);
    }
}

int lca(int u, int v) {
    if (dep[u] < dep[v]) swap(u, v);
    int jarak = dep[u] - dep[v];
    forn(i, 18) {
        if (jarak & (1 << i)) u = spt[u][i];
    }
    for (int i = 17; i >= 0; i--) {
        if (spt[u][i] != spt[v][i]) {
            u = spt[u][i];
            v = spt[v][i];
        }
    }
    while (u != v) {
        u = par[u];
        v = par[v];
    }
    return u;
}

int jarak (int u, int v) {
    return dep[u] + dep[v] - 2 * dep[lca(u, v)];
}

void procSpt() {
    forn(b, 18) {
        forn(i, adj.size()) {
            if (b) spt[i][b] = spt[spt[i][b - 1]][b - 1];
            else spt[i][b] = par[i];
        }
    }
}

void proc() {
    forn(i, vp.size()) {
        if (vp[i].first > vp[i].second) swap(vp[i].first, vp[i].second);
    }
    sort(vp.begin(), vp.end());
    vp.erase(unique(vp.begin(), vp.end()), vp.end());

    forn(i, vp.size()) {
        int u = vp[i].first, v = vp[i].second;
        int j = jarak(u, v);
        cy[j].push_back({u, v});
    }
}

void printcycle(int u, int v) {
    int _lca = lca(u, v);
    stack<int> rev;
    while (u != _lca) {
        rev.push(u+1);
        u = par[u];
    }
    cout << v + 1<< ' ';
    while (v != _lca) {
        v = par[v];
        cout << v + 1 << ' ';
    }
    while (!rev.empty()) {
        cout << rev.top() << (rev.size() == 1 ? "" : " ");
        rev.pop();
    }
    cout << '\n';
}

void solve() {
    int n;
    cin >> n;
    adj.resize(n);
    dep = vi(n, 0);
    par = vi(n, 0);
    vis = vi(n, 0);
    cy = vector<vector<pair<int, int>>>(n+2, vector<pair<int, int>>());
    spt = vector<vi>(n, vi(18, 0));


    forn(i, 2*n - 3) {
        int u, v;
        cin >> u >> v;
        --u, --v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    dfs(0);
    procSpt();
    proc();

    for(int i = cy.size() - 1; i >= 2; i--) {
        if (cy[i].size() > 1) {
            cout << i + 1 << '\n';
            printcycle(cy[i][0].first, cy[i][0].second);
            printcycle(cy[i][1].first, cy[i][1].second);
            return;
        }
    }



    cout << -1 << '\n';
    
}

int32_t main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    int t = 1;
    // cin >> t;
    while (t--) solve();

    return 0;
}