#include <bits/stdc++.h>
using namespace std;
const long long N = 100005;
vector<vector<long long> > adj(N), w(N);
long long out[N], col[N], res[N], cnt;
queue<long long> q;
void dfs(long long v, long long p) {
  for (auto &u : adj[v]) {
    if (u == p) continue;
    dfs(u, v);
  }
  for (auto &u : adj[v]) {
    if (u == p) continue;
    if (col[u] != col[v] && !res[u] && !res[v]) {
      res[u] = res[v] = ++cnt;
      q.push(v);
      q.push(u);
    }
  }
  return;
}
void bfs() {
  q.push(1);
  col[1] = 1;
  while (!q.empty()) {
    long long v = q.front();
    q.pop();
    for (auto &u : adj[v]) {
      if (!col[u]) {
        col[u] = col[v] % 2 + 1;
        q.push(u);
      }
    }
  }
  cnt = 0;
  dfs(1, 0);
  while (!q.empty()) {
    long long v = q.front();
    q.pop();
    for (auto &u : adj[v]) {
      if (!res[u]) {
        res[u] = res[v];
        q.push(u);
      }
    }
  }
  return;
}
int main() {
  long long n, i, j, v, u, ans;
  cin >> n;
  for (i = 0; i < n - 1; i++) {
    cin >> v >> u;
    adj[v].push_back(u);
    adj[u].push_back(v);
  }
  bfs();
  for (i = 1; i <= n; i++) w[res[i]].push_back(i);
  ans = 0;
  for (i = 1; i <= cnt; i++) {
    ans += (w[i].size() - 1) * 2;
    for (j = 0; j < w[i].size(); j++)
      out[w[i][j]] = w[i][(j + 1) % w[i].size()];
  }
  cout << ans << "\n";
  for (i = 1; i <= n; i++) cout << out[i] << " ";
  return 0;
}
