#include <vector>
#include <iostream>
#include <algorithm>
#include <functional>
using namespace std;
const int inf = 1012345678;
int main() {
	int N;
	cin >> N;
	vector<vector<int> > G(N);
	for (int i = 0; i < N - 1; ++i) {
		int a, b;
		cin >> a >> b; --a, --b;
		G[a].push_back(b);
		G[b].push_back(a);
	}
	vector<int> d(N);
	for (int i = 0; i < N - 1; ++i) {
		int a, b;
		cin >> a >> b; --a, --b;
		d[a] ^= 1;
		d[b] ^= 1;
	}
	vector<int> cnt(N);
	function<vector<int>(int, int)> dfs = [&](int pos, int pre) {
		cnt[pos] = d[pos];
		vector<int> ans = { 0, inf, inf };
		if (d[pos] == 1) ans[1] = 0;
		for (int i : G[pos]) {
			if (i == pre) continue;
			vector<int> res = dfs(i, pos);
			for (int j = 0; j <= 2; ++j) {
				if ((cnt[i] + j) % 2 == 1) ++res[j];
			}
			cnt[pos] ^= cnt[i];
			vector<int> ndp(3, inf);
			for (int j = 0; j <= 2; ++j) {
				for (int k = 0; j + k <= 2; ++k) {
					ndp[j + k] = min(ndp[j + k], ans[j] + res[k]);
				}
			}
			ans = ndp;
		}
		return ans;
	};
	vector<int> ret = dfs(0, -1);
	cout << N - 1 + ret[2] << endl;
	return 0;
}