#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < (n); i++)
#define repr(i, n) for (int i = (n) - 1; i >= 0; i--)
#define rep2(i, l, r) for (int i = (l); i < (r); i++)
#define repr2(i, l, r) for (int i = (r) - 1; i >= (l); i--)
#define range(a) a.begin(), a.end()

using namespace std;
using ll = long long;

void chmin(int &x, int y) {
  x = min(x, y);
}

int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  int n; cin >> n;
  vector<vector<int>> g(n);
  rep(i, n - 1) {
    int a, b; cin >> a >> b; a--; b--;
    g[a].push_back(b);
    g[b].push_back(a);
  }
  vector<int> deg(n);
  rep(i, n - 1) {
    int c, d; cin >> c >> d; c--; d--;
    deg[c]++;
    deg[d]++;
  }
  int ans = n - 1;
  vector<vector<int>> dp0(n, vector<int>(3, 1e9));
  vector<vector<int>> dp1(n, vector<int>(3, 1e9));
  auto dfs = [&](auto dfs, int u, int p) -> void {
    if (deg[u] % 2 == 0) {
      dp0[u][0] = 0;
    } else {
      dp1[u][0] = 0;
      dp0[u][1] = 0;
    }
    for (int v : g[u]) if (v != p) {
      dfs(dfs, v, u);
      vector<int> tmp0(3, 1e9);
      vector<int> tmp1(3, 1e9);
      rep(i, 3) rep(j, 3) if (i + j <= 2) {
        chmin(tmp0[i + j], dp0[u][i] + dp0[v][j]);
        chmin(tmp0[i + j], dp1[u][i] + dp1[v][j] + 1);
        chmin(tmp1[i + j], dp0[u][i] + dp1[v][j] + 1);
        chmin(tmp1[i + j], dp1[u][i] + dp0[v][j]);
      }
      dp0[u] = tmp0;
      dp1[u] = tmp1;
    }
  };
  dfs(dfs, 0, -1);
  cout << dp0[0][2] + (n - 1) << endl;
}