#include <bits/stdc++.h>
using namespace std;
const long long maxn = 2e5 + 5;
long long p[maxn];
long long dis[maxn];
long long dep[maxn];
long long par[maxn];
bool vis[maxn];
long long res[maxn];
long long n, cnt, maxd, rt1, rt2;
long long ans;
long long l;
struct node {
  long long v, next;
} e[maxn * 2];
void addEdge(long long u, long long v) {
  cnt++;
  e[cnt].v = v;
  e[cnt].next = p[u];
  p[u] = cnt;
}
void dfs(long long u, long long f) {
  for (long long i = p[u]; i != -1; i = e[i].next) {
    if (e[i].v == f) continue;
    par[e[i].v] = u;
    dep[e[i].v] = dep[u] + 1;
    if (dep[e[i].v] > dep[maxd]) maxd = e[i].v;
    dfs(e[i].v, u);
  }
}
void dfs2(long long u, long long f) {
  for (long long i = p[u]; i != -1; i = e[i].next) {
    if (e[i].v == f) continue;
    dis[e[i].v] = dis[u] + 1;
    dfs2(e[i].v, u);
  }
}
void dfs3(long long u, long long f) {
  for (long long i = p[u]; i != -1; i = e[i].next) {
    if (e[i].v == f) continue;
    dfs3(e[i].v, u);
  }
  if (!vis[u]) cout << u << ' ' << res[u] << ' ' << u << '\n';
}
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  memset(p, -1, sizeof(p));
  cin >> n;
  for (long long i = 1; i < n; i++) {
    long long u, v;
    cin >> u >> v;
    addEdge(u, v);
    addEdge(v, u);
  }
  dfs(1, -1);
  dep[maxd] = 0;
  rt1 = maxd;
  par[maxd] = -1;
  dfs(maxd, -1);
  rt2 = maxd;
  l = dep[rt2];
  for (long long i = rt2; i != -1; i = par[i]) vis[i] = 1;
  dfs2(rt2, -1);
  for (long long i = 1; i <= n; i++) {
    if (vis[i] == 0) {
      if (dep[i] > dis[i]) {
        res[i] = rt1;
        ans += dep[i];
      } else {
        res[i] = rt2;
        ans += dis[i];
      }
    }
  }
  ans += (l + 1) * l / 2;
  cout << ans << '\n';
  dfs3(rt1, -1);
  for (long long i = rt2; i != rt1; i = par[i])
    cout << i << ' ' << rt1 << ' ' << i << '\n';
}
