#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  vector<vector<int>> g(n);
  vector<pair<int, int>> e(n - 1);
  for (int i = 0; i < n - 1; ++i) {
    int u, v;
    cin >> u >> v;
    --u;
    --v;
    g[u].push_back(v);
    g[v].push_back(u);
    e[i] = make_pair(u, v);
  }
  vector<int> col(n);
  for (int &i : col) {
    cin >> i;
  }
  int diff = 0;
  for (auto i : e) {
    if (col[i.first] != col[i.second]) {
      ++diff;
    }
  }
  for (int i = 0; i < n; ++i) {
    int ctr = 0;
    for (int j : g[i]) {
      if (col[i] != col[j]) {
        ++ctr;
      }
    }
    if (ctr == diff) {
      cout << "YES\n" << i + 1;
      return 0;
    }
  }
  cout << "NO";
  return 0;
}
