#include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (int)n; i++)
using namespace std;
using ll = long long;

int n;
vector<vector<int>> g;
vector<int> be;
int max_dist = 0;

pair<int, ll> dfs(int v, int p) {
    pair<int, ll> ret = {-1, 0};
    vector<int> vec;
    if(be[v] % 2) {
        vec.push_back(0);
    }
    rep(i, g[v].size()) {
        if(g[v][i] == p) continue;
        auto tmp = dfs(g[v][i], v);
        ret.second += tmp.second;
        if(tmp.first != -1) {
            vec.push_back(tmp.first + 1);
            ret.second++;
        }
    }
    sort(vec.begin(), vec.end());
    if((int)vec.size() >= 2) {
        max_dist = max(max_dist, vec[(int)vec.size() - 1]
                       + vec[(int)vec.size() - 2]);
    }
    if((int)vec.size() % 2 == 1) {
        ret.first = vec[(int)vec.size() - 1];
    }
    return ret;
}

int main() {
    cin >> n;
    g.resize(n);
    be.assign(n, 0);
    rep(i, n - 1) {
        int a, b;
        cin >> a >> b;
        a--; b--;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    rep(i, n - 1) {
        int c, d;
        cin >> c >> d;
        c--; d--;
        be[c]++;
        be[d]++;
    }
    auto tmp = dfs(0, -1);
    cout << tmp.second + n - 1 - max_dist << endl;
    return 0;
}