#include <bits/stdc++.h>
using namespace std;
void __print(int first) { cerr << first; }
void __print(long first) { cerr << first; }
void __print(long long first) { cerr << first; }
void __print(unsigned first) { cerr << first; }
void __print(unsigned long first) { cerr << first; }
void __print(unsigned long long first) { cerr << first; }
void __print(float first) { cerr << first; }
void __print(double first) { cerr << first; }
void __print(long double first) { cerr << first; }
void __print(char first) { cerr << '\'' << first << '\''; }
void __print(const char *first) { cerr << '\"' << first << '\"'; }
void __print(const string &first) { cerr << '\"' << first << '\"'; }
void __print(bool first) { cerr << (first ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &first) {
  cerr << '{';
  __print(first.first);
  cerr << ',';
  __print(first.second);
  cerr << '}';
}
template <typename T>
void __print(const T &first) {
  int f = 0;
  cerr << '{';
  for (auto &i : first) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
vector<set<long long> > vect;
long long deleted = 0;
map<long long, long long> mp;
long long visited[100010];
void dfs(long long parent, long long node) {
  ;
  set<long long> temp = vect[node];
  for (auto &child : temp) {
    if (child != parent) dfs(node, child);
  }
  long long cnt = 0;
  for (auto &child : vect[node]) {
    if (child != parent) cnt++;
  }
  if (cnt >= 1) {
    if (parent == 0) return;
    deleted++;
    vect[parent].erase(node);
    vect[node].erase(parent);
  }
}
void dfs1(long long node) {
  visited[node] = 1;
  for (auto &child : vect[node]) {
    if (!visited[child]) {
      swap(mp[node], mp[child]);
      dfs1(child);
    }
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long n;
  cin >> n;
  vect.resize(n + 1);
  long long u, v;
  for (long long i = 0; i < n - 1; i++) {
    cin >> u >> v;
    vect[u].insert(v);
    vect[v].insert(u);
  }
  set<long long> temp = vect[1];
  dfs(0, 1);
  if (vect[1].size() == 0) {
    vect[1].insert(*(temp.begin()));
    vect[*(temp.begin())].insert(1);
    deleted--;
  };
  cout << 2 * (n - deleted - 1) << "\n";
  for (long long i = 1; i < n + 1; i++) mp[i] = i;
  for (long long i = 1; i < n + 1; i++) {
    if (!visited[i]) dfs1(i);
  }
  for (long long i = 1; i < n + 1; i++) cout << mp[i] << " ";
}
