#include <bits/stdc++.h>
using namespace std;
vector<vector<long long> > adj;
vector<bool> visited;
long long longest(long long v, long long &ans) {
  visited[v] = true;
  long long maxDist = 0;
  ans = v;
  for (long long i = 0; i < adj[v].size(); i++) {
    long long v1 = adj[v][i];
    if (!visited[v1]) {
      long long tempDist, tempV;
      tempDist = 1 + longest(v1, tempV);
      if (tempDist > maxDist) {
        maxDist = tempDist;
        ans = tempV;
      }
    }
  }
  return maxDist;
}
bool trace(long long v, long long target, vector<bool> &arr) {
  visited[v] = true;
  if (v == target) {
    arr[v] = true;
  } else {
    arr[v] = false;
    for (long long i = 0; i < adj[v].size(); i++) {
      long long v1 = adj[v][i];
      if (!visited[v1]) {
        arr[v] = arr[v] || trace(v1, target, arr);
      }
    }
  }
  return arr[v];
}
void dist(long long v, vector<long long> &arr) {
  visited[v] = true;
  for (long long i = 0; i < adj[v].size(); i++) {
    long long v1 = adj[v][i];
    if (!visited[v1]) {
      arr[v1] = 1 + arr[v];
      dist(v1, arr);
    }
  }
}
int main() {
  long long n;
  cin >> n;
  adj.clear();
  adj.resize(n);
  for (long long i = 0; i < n - 1; i++) {
    long long a, b;
    cin >> a >> b;
    a--;
    b--;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }
  visited.clear();
  visited.resize(n, false);
  long long v1;
  longest(0, v1);
  visited.clear();
  visited.resize(n, false);
  long long v2;
  longest(v1, v2);
  vector<bool> mark(n, false);
  visited.clear();
  visited.resize(n, false);
  trace(v1, v2, mark);
  vector<long long> dist1(n, 0);
  visited.clear();
  visited.resize(n, false);
  dist1[v1] = 0;
  dist(v1, dist1);
  vector<long long> dist2(n, 0);
  visited.clear();
  visited.resize(n, false);
  dist2[v2] = 0;
  dist(v2, dist2);
  long long ans = 0;
  vector<pair<long long, pair<long long, long long> > > arr1;
  vector<pair<long long, pair<long long, long long> > > arr2;
  for (long long i = 0; i < n; i++) {
    if (!mark[i]) {
      if (dist1[i] >= dist2[i]) {
        ans += dist1[i];
        arr1.push_back(make_pair(dist1[i], make_pair(i, v1)));
      } else {
        ans += dist2[i];
        arr1.push_back(make_pair(dist2[i], make_pair(i, v2)));
      }
    } else {
      if (i != v1) arr2.push_back(make_pair(dist1[i], make_pair(i, v1)));
      ans += dist1[i];
    }
  }
  cout << ans << endl;
  sort(arr1.begin(), arr1.end());
  reverse(arr1.begin(), arr1.end());
  sort(arr2.begin(), arr2.end());
  reverse(arr2.begin(), arr2.end());
  for (long long i = 0; i < arr1.size(); i++) {
    cout << arr1[i].second.first + 1 << " " << arr1[i].second.second + 1 << " "
         << arr1[i].second.first + 1 << endl;
  }
  for (long long i = 0; i < arr2.size(); i++) {
    cout << arr2[i].second.first + 1 << " " << arr2[i].second.second + 1 << " "
         << arr2[i].second.first + 1 << endl;
  }
  return 0;
}
