#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
#define int ll
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector< vi > vvi;
typedef vector< vvi > vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;
typedef complex<double> base;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for(int i = 0; i < int(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cerr << (#x) << " = " << (x) << endl;

#ifdef MAX_HOME
#define cerr cout
#else
#define cerr if (false) cerr
#endif

const double PI = 2 * acos(0.0);
#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";

template <class T0, class T1>
inline ostream & operator << (ostream &out, pair<T0, T1> &a) {
    return out << "{" << a.first << ", " << a.second << "}";
}

template <class T0, class T1, class T2>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << "}";
}

template <class T0, class T1, class T2, class T3>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2, T3> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ", " <<  get<3>(a) << "}";
}

template<class T>
inline ostream & operator << (ostream &out, vector<T> &a) {
    out << "[";
    fori (i, a.size())
        out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
    return out;
}



void smain();

signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

#ifdef MAX_HOME
    freopen("input.txt", "r", stdin);
    clock_t start = clock();
#endif
    cout << setprecision(12) << fixed;
    smain();
#ifdef MAX_HOME
    cout << "\n\n\n\nTOTAL EXECUTION TIME: " << float( clock () - start ) /  CLOCKS_PER_SEC << endl;
#endif
    return 0;
}


const int N = 2e5 + 100;
ll M[2];
ll pwx[N][2];

struct DoubleHash {
    ll a, b, cnt;
};

const DoubleHash operator + (const DoubleHash &f, const DoubleHash &s) {
    return {(f.a * pwx[s.cnt][0] + s.a) % M[0], (f.b * pwx[s.cnt][1] + s.b) % M[1], f.cnt + s.cnt};
}

const bool operator < (const DoubleHash &f, const DoubleHash &s) {
    return f.a < s.a || (f.a == s.a && (f.b < s.b || (f.b == s.b && f.cnt < s.cnt)));
}

struct Tree {
    vector<DoubleHash> t;
    Tree(int n) {
        t.resize(n << 2);
    }


    void build(int v, int tl, int tr, vector<DoubleHash> &child) {
        if (tl == tr) {
            t[v] = child[tl];
            return;
        }
        int tm = tl + tr >> 1;
        build(v << 1, tl, tm, child);
        build(v << 1 | 1, tm + 1, tr, child);
        t[v] = t[v << 1] + t[v << 1 | 1];
    }

    void upd(int v, int tl, int tr, int pos, DoubleHash dh) {
        if (tl == tr) {
            t[v] = dh;
            return;
        }
        int tm = tl + tr >> 1;
        if (pos <= tm) upd(v << 1, tl, tm, pos, dh);
        else upd(v << 1 | 1, tm + 1, tr, pos, dh);
        t[v] = t[v << 1] + t[v << 1 | 1];
    }
};

set<DoubleHash> solve(vvi &_g, bool big, set<DoubleHash> prev) {

    int n = (int)_g.size() - 1;
    vvi g(n + 1);
    function<void(int, int)> hang;

    hang = [&] (int v, int par) -> void {
        for (int to : _g[v]) {
            if (to == par) continue;
            hang(to, v);
            g[v].push_back(to);
        }
    };

    vl cnt(n + 1, 0);
    vector<DoubleHash> hs(n + 1);

    function<void(int)> dfs;

    dfs = [&] (int v) -> void {
        for (int to : g[v]) dfs(to);
        cnt[v] = 1;
        vector<DoubleHash> child;
        for (int to : g[v]) {
            cnt[v] += cnt[to];
            child.push_back(hs[to]);
        }
        sort(ALL(child));
        hs[v] = {1, 1, 1};
        for (auto item : child) {
            hs[v] = hs[v] + item;
        }
        DoubleHash fin = {2, 2, 1};
        hs[v] = hs[v] + fin;
    };

    function<void(int, DoubleHash)> dfs2;
    vector<DoubleHash> res(n + 1);
    set<DoubleHash> ans;
    dfs2 = [&] (int v, DoubleHash hsup) -> void {
        if (big) {
            if (g[v].size() == 0) {
                if (prev.count(hsup)) {
                    ans.insert({v, v, v});
                }
            }
        }
        ll cntup = n - cnt[v];
        vector<DoubleHash> child;
        child.push_back(hsup);
        for (int to : g[v]) {
            child.push_back(hs[to]);
        }
        sort(ALL(child));
        res[v] = {1, 1, 1};
        for (auto item : child) {
            res[v] = res[v] + item;
        }
        DoubleHash fin = {2, 2, 1};
        res[v] = res[v] + fin;
        if (!big) {
            ans.insert(res[v]);
        }
        Tree tree(child.size());
        int sz = child.size();
        tree.build(1, 0, sz - 1, child);

        for (int to : g[v]) {
            int ind = upper_bound(ALL(child), hs[to]) - child.begin();
            ind--;

            tree.upd(1, 0, sz - 1, ind, {0, 0, 0});
            DoubleHash lol = tree.t[1];
            DoubleHash st = {1, 1, 1};
            DoubleHash fin = {2, 2, 1};
            lol = st + lol + fin;

            dfs2(to, lol);
            tree.upd(1, 0, sz - 1, ind, hs[to]);
        }
    };


    hang(1, -1);
    dfs(1);
    dfs2(1, {0, 0, 0});

    if (big && g[1].size() == 1) {
        if (prev.count(hs[g[1][0]])) ans.insert({1, 1, 1});
    }
    return ans;
}

int geth(string s) {
//    int ret = 0;
//    int n = s.size();
//    for (int i = 0; i < n; ++i) {
//        ret = (ret *  + (s[i] - '(' + 1)) % M;
//    }
//    return ret;
}

bool is_prime(ll x) {
    for (int i = 2; i * i <= x; ++i) if (x % i == 0) return false;
    return true;
}

void smain() {

    fori (z, 2) {
        M[z] = 1e9 + rng() % 10000000;
        ll x = 3 + rng() % 100;
        for (; !is_prime(M[z]); ++M[z]);
        for (; !is_prime(x); ++x);
        pwx[0][z] = 1;
        for (int i = 1; i < N; ++i) {
            pwx[i][z] = x * pwx[i - 1][z] % M[z];
        }
    }



    int n;
    cin >> n;
    vvi g1(n + 1);
    vvi g2(n + 2);

    fori (i, n - 1) {
        int u, v;
        cin >> u >> v;
        g1[u].push_back(v);
        g1[v].push_back(u);
    }
    fori (i, n) {
        int u, v;
        cin >> u >> v;
        g2[u].push_back(v);
        g2[v].push_back(u);
    }

    set<DoubleHash> dummy;
    set<DoubleHash> hashs = solve(g1, false, dummy);
    set<DoubleHash> ans = solve(g2, true, hashs);
    assert(!ans.empty());
    cout << (*ans.begin()).a;
}