#include <bits/stdc++.h>
using namespace std;
const int N = 200005;
vector<int> g[N];
int ds[N], de[N], diam[N], par[N];
int vis[N];
void dfs(int v, int p, int d, int dist[]) {
  dist[v] = d;
  par[v] = p;
  for (int u : g[v]) {
    if (u != p) dfs(u, v, d + 1, dist);
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cout << setprecision(32);
  int n;
  cin >> n;
  for (int i = 1; i < n; i++) {
    int x, y;
    cin >> x >> y;
    g[x].push_back(y);
    g[y].push_back(x);
  }
  dfs(1, 0, 1, ds);
  int s = 1;
  for (int i = 1; i <= n; i++) {
    if (ds[i] > ds[s]) s = i;
  }
  dfs(s, 0, 1, ds);
  int e = s;
  for (int i = 1; i <= n; i++) {
    if (ds[i] > ds[e]) e = i;
  }
  int v = e;
  vector<int> vec;
  while (v) {
    vec.push_back(v);
    diam[v] = 1;
    v = par[v];
  }
  dfs(e, 0, 1, de);
  vector<pair<int, pair<int, char> > > iic;
  for (int i = 1; i <= n; i++) {
    if (!diam[i]) {
      iic.push_back({ds[i], {i, 's'}});
      iic.push_back({de[i], {i, 'e'}});
    }
  }
  sort(iic.rbegin(), iic.rend());
  memset(vis, 0, sizeof(vis));
  vector<pair<pair<int, int>, int> > ans;
  long long sum = 0;
  for (auto pp : iic) {
    int ind = pp.second.first;
    if (vis[ind]) continue;
    vis[ind] = 1;
    sum += pp.first - 1;
    if (pp.second.second == 's') {
      ans.push_back({{ind, s}, ind});
    } else {
      ans.push_back({{ind, e}, ind});
    }
  }
  sum += vec.size() * 1LL * (vec.size() - 1) / 2;
  for (int i = 0; i + 1 < vec.size(); i++) {
    ans.push_back({{vec[i], vec.back()}, vec[i]});
  }
  cout << sum << '\n';
  for (auto ppp : ans) {
    cout << ppp.first.first << " " << ppp.first.second << " " << ppp.second
         << '\n';
  }
  return 0;
}
