#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <chrono>
#define _USE_MATH_DEFINES
#include <cmath>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iostream>
#include <iomanip>
#include <iterator>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
using namespace std;

#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()

const int INF = 0x3f3f3f3f;
const long long LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-8;
const int MOD = 1000000007; // 998244353;
const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};

struct IOSetup {
  IOSetup() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    cerr << fixed << setprecision(10);
  }
} iosetup;
/*-------------------------------------------------*/
vector<int> graph[200000];
int subtree[200000] = {}, dp[200000][3] = {};
bool odd[200000] = {};

void dfs1(int par, int ver) {
  if (odd[ver]) subtree[ver] = 1;
  for (int e : graph[ver]) if (e != par) {
    dfs1(ver, e);
    subtree[ver] += subtree[e];
  }
}

void dfs2(int par, int ver) {
  for (int e : graph[ver]) {
     if (e != par) dfs2(ver, e);
  }
  dp[ver][0] = 0;
  for (int e : graph[ver]) if (e != par) {
    dp[ver][0] += dp[e][0];
    if (subtree[e] & 1) ++dp[ver][0];
  }
  if (subtree[ver] >= 1) {
    int mn = INF;
    for (int e : graph[ver]) if (e != par) {
      int zero = dp[e][0] + (subtree[e] & 1);
      int one = dp[e][1] + (subtree[e] % 2 == 0);
      mn = min(mn, one - zero);
    }
    dp[ver][1] = min(dp[ver][1], dp[ver][0] + mn);
    if (odd[ver]) dp[ver][1] = min(dp[ver][1], dp[ver][0]);
    if (subtree[ver] >= 2) {
      int mn2 = INF;
      for (int e : graph[ver]) if (e != par) {
        int zero = dp[e][0] + (subtree[e] & 1);
        int two = dp[e][2] + (subtree[e] & 1);
        mn2 = min(mn2, two - zero);
      }
      dp[ver][2] = min(dp[ver][2], dp[ver][0] + mn2);
      vector<int> mn1;
      for (int e : graph[ver]) if (e != par) {
        int zero = dp[e][0] + (subtree[e] & 1);
        int one = dp[e][1] + (subtree[e] % 2 == 0);
        mn1.emplace_back(one - zero);
      }
      if (mn1.size() >= 2) {
        sort(ALL(mn1));
        int mnmn = mn1[0] + mn1[1];
        dp[ver][2] = min(dp[ver][2], dp[ver][0] + mnmn);
      }
      if (odd[ver]) dp[ver][2] = min(dp[ver][2], dp[ver][0] + mn);
    }
  }
}

int main() {
  memset(dp, INF, sizeof(dp));
  int n; cin >> n;
  REP(_, n - 1) {
    int a, b; cin >> a >> b; --a; --b;
    graph[a].emplace_back(b);
    graph[b].emplace_back(a);
  }
  REP(_, n - 1) {
    int c, d; cin >> c >> d; --c; --d;
    odd[c] = !odd[c];
    odd[d] = !odd[d];
  }
  dfs1(-1, 0);
  dfs2(-1, 0);
  cout << n - 1 + min(dp[0][0], dp[0][2]) << '\n';
  return 0;
}