#include <bits/stdc++.h>
using namespace std;
constexpr int MOD = 1000000007;
template <typename T>
std::istream& operator>>(std::istream& i, vector<T>& t) {
  for (auto& v : t) {
    i >> v;
  }
  return i;
}
template <typename T>
std::ostream& operator<<(std::ostream& o, const vector<T>& t) {
  for (size_t i = 0; i < t.size(); ++i) {
    o << t[i] << " \n"[i == t.size() - 1];
  }
  return o;
}
template <typename T, typename U>
std::istream& operator>>(std::istream& i, pair<T, U>& p) {
  i >> p.first >> p.second;
  return i;
}
template <typename T>
using minheap = priority_queue<T, vector<T>, greater<T>>;
template <typename T>
using maxheap = priority_queue<T, vector<T>, less<T>>;
auto fraclt = [](const std::pair<int, int>& a, const std::pair<int, int>& b) {
  return (long long)a.first * b.second < (long long)b.first * a.second;
};
struct cmpfrac {
  bool operator()(const std::pair<int, int>& a,
                  const std::pair<int, int>& b) const {
    return (long long)a.first * b.second < (long long)b.first * a.second;
  }
};
struct input {
  std::istream& cin;
  explicit input(std::istream& cin) : cin(cin) {}
  template <typename T>
  operator T() {
    T t;
    cin >> t;
    return t;
  }
};
int logceil(long long first) {
  int b = 0;
  while (first) {
    first >>= 1;
    ++b;
  }
  return b;
}
namespace std {
template <typename T, typename U>
struct hash<pair<T, U>> {
  hash<T> t;
  hash<U> u;
  size_t operator()(const pair<T, U>& p) const {
    return t(p.first) ^ (u(p.second) << 7);
  }
};
}  // namespace std
template <typename T, typename F>
T bsh(T l, T h, const F& f) {
  T r = -1, m;
  while (l <= h) {
    m = (l + h) / 2;
    if (f(m)) {
      l = m + 1;
      r = m;
    } else {
      h = m - 1;
    }
  }
  return r;
}
template <typename T, typename F>
T bsl(T l, T h, const F& f) {
  T r = -1, m;
  while (l <= h) {
    m = (l + h) / 2;
    if (f(m)) {
      h = m - 1;
      r = m;
    } else {
      l = m + 1;
    }
  }
  return r;
}
template <typename T>
T gcd(T a, T b) {
  if (a < b) swap(a, b);
  return b ? gcd(b, a % b) : a;
}
template <typename T>
class vector2 : public vector<vector<T>> {
 public:
  vector2() {}
  vector2(size_t a, size_t b, T t = T())
      : vector<vector<T>>(a, vector<T>(b, t)) {}
};
template <typename T>
class vector3 : public vector<vector<vector<T>>> {
 public:
  vector3() {}
  vector3(size_t a, size_t b, size_t c, T t = T())
      : vector<vector<vector<T>>>(a, vector<vector<T>>(b, vector<T>(c, t))) {}
};
class TaskC {
 public:
  int N, M;
  vector<vector<int>> E, S;
  vector<int> V;
  int col;
  void dfs(int u, int ig) {
    int c = 1;
    set<int> C;
    for (int v : S[u]) {
      if (V[v]) {
        C.insert(V[v]);
      }
    }
    for (int v : S[u]) {
      if (!V[v]) {
        while (C.find(c) != C.end()) c++;
        V[v] = c;
        C.insert(V[v]);
      }
    }
    col = max(col, c);
    for (int v : E[u])
      if (v != ig) dfs(v, u);
  }
  void solve(istream& cin, ostream& cout) {
    col = 0;
    cin >> N >> M;
    V = vector<int>(M, 0);
    E.clear();
    E.resize(N);
    S.clear();
    S.resize(N);
    for (int i = 0; i < N; ++i) {
      int s;
      cin >> s;
      S[i].resize(s);
      for (int j = 0; j < s; ++j) {
        int c;
        cin >> c;
        --c;
        S[i][j] = c;
      }
    }
    for (int i = 0; i < N - 1; ++i) {
      int u, v;
      cin >> u >> v;
      --u;
      --v;
      E[u].push_back(v);
      E[v].push_back(u);
    }
    dfs(0, -1);
    for (int& v : V) v = max(v, 1);
    cout << max(col, 1) << endl;
    cout << V;
  }
};
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  TaskC solver;
  std::istream& in(std::cin);
  std::ostream& out(std::cout);
  solver.solve(in, out);
  return 0;
}
