#include <bits/stdc++.h>
using namespace std;
template <typename TA, typename TB>
ostream &operator<<(ostream &ostm, const pair<TA, TB> &p) {
  ostm << "(" << p.first << "," << p.second << ")";
  return ostm;
}
template <typename T>
ostream &operator<<(ostream &ostm, const vector<T> &v) {
  ostm << "[ ";
  for (auto i : v) ostm << i << " ";
  ostm << "]";
  return ostm;
}
template <typename TA, typename TB>
ostream &operator<<(ostream &ostm, const map<TA, TB> &mp) {
  ostm << "[ ";
  for (auto &it : mp) ostm << it << " ";
  ostm << "]";
  return ostm;
}
template <typename T>
ostream &operator<<(ostream &ostm, const set<T> &s) {
  ostm << "[ ";
  for (auto &it : s) ostm << it << " ";
  ostm << "]";
  return ostm;
}
template <typename T>
ostream &operator<<(ostream &ostm, const stack<T> &inp) {
  stack<T> st = inp;
  ostm << "[ ";
  while (!st.empty()) {
    ostm << st.top() << " ";
    st.pop();
  }
  ostm << "]";
  return ostm;
}
template <typename T>
ostream &operator<<(ostream &ostm, const queue<T> &inp) {
  queue<T> q = inp;
  ostm << "[ ";
  while (!q.empty()) {
    ostm << q.front() << " ";
    q.pop();
  }
  ostm << "]";
  return ostm;
}
template <typename T>
ostream &operator<<(ostream &ostm, const priority_queue<T> &inp) {
  priority_queue<T> pq = inp;
  ostm << "[ ";
  while (!pq.empty()) {
    ostm << pq.top() << " ";
    pq.pop();
  }
  ostm << "]";
  return ostm;
}
template <typename T>
ostream &operator<<(ostream &ostm, const deque<T> &inp) {
  deque<T> dq = inp;
  ostm << "[ ";
  while (!dq.empty()) {
    ostm << dq.front() << " ";
    dq.pop_front();
  }
  ostm << "]";
  return ostm;
}
inline int gtx() {
  const int N = 1048576;
  static char __buffer[N];
  static char *__p = __buffer, *__end = __buffer;
  if (__p == __end) {
    if ((__end = __buffer + fread(__buffer, 1, N, stdin)) == __buffer)
      return EOF;
    __p = __buffer;
  }
  return *__p++;
}
template <typename T>
inline bool rit(T &x) {
  char c = 0;
  bool fg = 0;
  while (c = gtx(), (c < '0' && c != '-') || c > '9')
    if (c == EOF) return false;
  c == '-' ? (fg = 1, x = 0) : (x = c & 15);
  while (c = gtx(), c >= '0' && c <= '9') x = x * 10 + (c & 15);
  if (fg) x = -x;
  return true;
}
template <typename T, typename... Args>
inline bool rit(T &x, Args &...args) {
  return rit(x) && rit(args...);
}
inline void pit(int x) { printf("%d", x); }
inline void pln(long long x) { printf("%I64d", x); }
template <typename... Args>
inline void pit(int x, Args... args) {
  printf("%d ", x);
  pit(args...);
}
template <typename... Args>
inline void pln(long long x, Args... args) {
  printf("%I64d ", x);
  pit(args...);
}
void JIZZ() {
  cout << "";
  exit(0);
}
const long double PI = 3.14159265358979323846264338327950288;
const long double eps = 1e-8;
const long long mod = 1e9 + 7;
set<int> ic[300005];
vector<int> G[300005];
int c[300005], mxc;
void dfs(int now, int fa) {
  ;
  ;
  set<int> u;
  for (int i : ic[now]) {
    if (c[i]) u.insert(c[i]);
  }
  int ptr = 1;
  for (int i : ic[now]) {
    if (c[i]) continue;
    while (u.find(ptr) != u.end()) ++ptr;
    c[i] = ptr;
    mxc = max(mxc, c[i]);
    ;
    ;
    u.insert(ptr);
    ++ptr;
  }
  for (int i : G[now]) {
    if (i == fa) continue;
    dfs(i, now);
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  ;
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  for (int i = 1; i <= n; ++i) {
    int c;
    cin >> c;
    while (c--) {
      int c;
      cin >> c;
      ic[i].insert(c);
    }
  }
  for (int i = 1; i < n; ++i) {
    int u, v;
    cin >> u >> v;
    G[u].push_back(v);
    G[v].push_back(u);
  }
  dfs(1, 1);
  cout << max(1, mxc) << '\n';
  for (int i = 1; i <= m; ++i) {
    cout << max(1, c[i]) << " ";
  }
}
