/*
_.-- ,.--.
.' .' /
@ |'..--------._
/ \._/ '.
/ .-.- \
( / \ \
\\ '. | #
\\ \ -. /
:\ | )._____.' \
" | / \ | \ )
| |./' :__ \.-'
'--'
*/
#include<bits/stdc++.h>
#define ll long long
#define llll pair<ll,ll>
#define ii pair<int,int>
#define fi first
#define se second
#define FOR(i,l,r) for(int i=l;i<=r;i++)
#define FOD(i,r,l) for(int i=r;i>=l;i--)
#define ull unsigned long long
#define iii pair<int,ii>
#define iv pair<pii,ii>
#define db double
#define ld long double
#define pb push_back
#define tdk "kfph"
using namespace std;
const int dx[] = {1, -1, 0, 0};
const int dy[] = {0, 0, -1, 1};
const int dxx[] = {1, 1, -1, -1, 2, 2, -2, -2};
const int dyy[] = {2, -2, 2, -2, 1, -1, 1, -1};
const ll INF=1e18;
const int N=1e5+5;
vector<int> a,g[N];
int n;
ll res;
int ans[N],sz[N],cen;
void dfs(int u,int par)
{
sz[u]=1;
for(int v:g[u])
{
if(v!=par)
{
dfs(v,u);
sz[u]+=sz[v];
}
}
}
int findc(int u,int par)
{
for(int v:g[u])
{
if(sz[v]*2>sz[1] and v!=par)
{
return findc(v,u);
}
}
return u;
}
void caldis(int u,int par,int h)
{
res+=h*2;
a.pb(u);
for(int v:g[u])
{
if(v!=par) caldis(v,u,h+1);
}
}
void kfph()
{
cin >> n;
for(int i=1;i<n;i++)
{
int u,v;
cin >> u >> v;
g[u].pb(v);
g[v].pb(u);
}
dfs(1,-1);
cen=findc(1,-1);
caldis(cen,-1,0);
for(int i=0;i<n;i++)
{
ans[a[i]-1]=a[(i+n/2)%n];
}
cout << res<< '\n';
for(int i=0;i<n;i++)
{
cout << ans[i] << ' ';
}
}
int main()
{
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
if(fopen(tdk".inp","r"))
{
freopen(tdk".inp","r",stdin);
freopen(tdk".out","w",stdout);
}
int t=1;
//cin >> t;
while(t--)
{
kfph();
}
return 0;
}
