//cre: johutha
//greedy idea on cf tutorial
#include <iostream>
#include <vector>
#include <algorithm>
#define int int64_t
using namespace std;
struct graph
{
int n;
vector<vector<int>> adjlist;
vector<int> pre;
vector<int> subtc;
int d = 0;
void dfs(int curr, int par)
{
pre.emplace_back(curr);
subtc[curr] = 1;
for (auto next : adjlist[curr])
{
if (next == par) continue;
dfs(next, curr);
subtc[curr] += subtc[next];
d += 2*min(subtc[next], n - subtc[next]);
}
}
void solve()
{
subtc.resize(n, 0);
dfs(0, -1);
cout << d << "\n";
vector<int> sol(n);
for (int i = 0; i < n; i++)
{
sol[pre[(i + n/2) % n]] = pre[i];
}
for (auto i : sol)
{
cout << i + 1 << " ";
}
cout << "\n";
}
};
signed main()
{
int n;
cin >> n;
graph g;
g.n = n;
g.adjlist.resize(n);
for (int i = 0; i < n - 1; i++)
{
int a, b;
cin >> a >> b; a--; b--;
g.adjlist[a].push_back(b);
g.adjlist[b].push_back(a);
}
g.solve();
}
