#include <bits/stdc++.h>
using namespace std;
const int N = 200200;
int n;
vector<int> adj[N];
int deg[N], dis[N];
int best, mx, first = -1, second = -1;
void dfs(int v, int p = -1, int cur = 0) {
  dis[v] = cur;
  if (cur > mx) {
    best = v;
    mx = cur;
  }
  for (int u : adj[v]) {
    if (u == p) continue;
    dfs(u, v, cur + 1);
  }
}
void go(int v, int p, int cur, vector<int>& all) {
  all[v] = cur;
  for (int u : adj[v]) {
    if (u == p) continue;
    go(u, v, cur + 1, all);
  }
}
int main() {
  cin >> n;
  for (int i = 0; i < n - 1; i++) {
    int a, b;
    cin >> a >> b;
    adj[a].push_back(b);
    adj[b].push_back(a);
    deg[a]++;
    deg[b]++;
  }
  dfs(1);
  mx = -1;
  int v = best;
  dfs(v);
  mx = best;
  vector<int> dis_v(n + 1), dis_u(n + 1);
  go(v, -1, 0, dis_v);
  go(mx, -1, 0, dis_u);
  long long int ans = 0;
  vector<vector<int>> an;
  auto add = [&](int a, int b, int c) { an.push_back({a, b, c}); };
  vector<int> all;
  vector<bool> mark(n + 1);
  for (int i = 1; i <= n; i++) {
    if (i == v || i == mx) continue;
    if (deg[i] == 1) {
      all.push_back(i);
    }
  }
  int cnt = 0;
  for (int i = 0; i < (int)all.size(); i++) {
    int it = all[i];
    cnt++;
    mark[it] = 1;
    if (dis_v[it] > dis_u[it]) {
      ans += dis_v[it];
      add(it, v, it);
    } else {
      ans += dis_u[it];
      add(it, mx, it);
    }
    for (int u : adj[it]) {
      deg[u]--;
      if (deg[u] == 1) all.push_back(u);
    }
  }
  assert(n - cnt == dis_v[mx] + 1);
  all.clear();
  for (int i = 1; i <= n; i++) {
    if (i != v && !mark[i] && deg[i] == 1) {
      all.push_back(i);
    }
  }
  for (int i = 0; i < (int)all.size(); i++) {
    ans += dis_v[all[i]];
    cnt++;
    add(v, all[i], all[i]);
    for (int u : adj[all[i]]) {
      deg[u]--;
      if (deg[u] == 1) all.push_back(u);
    }
  }
  assert(cnt == n - 1);
  cout << ans << '\n';
  for (auto it : an) {
    cout << it[0] << ' ' << it[1] << ' ' << it[2] << '\n';
  }
  return 0;
}
