#include <bits/stdc++.h>
using namespace std;
const int maxn = 200010;
int len, u, v;
long long nAns = 0;
vector<int> g[maxn];
int d[maxn], rt[maxn];
bool dm[maxn];
pair<int, int> pAns[maxn];
void dfsD(int id, int fa) {
  int i, nxt;
  for (i = 0; i < g[id].size(); i++) {
    nxt = g[id][i];
    if (nxt == fa) continue;
    rt[nxt] = id;
    d[nxt] = d[id] + 1;
    dfsD(nxt, id);
  }
}
void dfs(int id, int di) {
  int i, nxt;
  for (i = 0; i < g[id].size(); i++) {
    nxt = g[id][i];
    if (d[nxt] <= d[id]) continue;
    if (dm[nxt])
      dfs(nxt, nxt);
    else
      dfs(nxt, di);
  }
  if (!dm[id]) {
    if (d[di] * 2 > d[v]) {
      nAns += d[id];
      pAns[++len] = make_pair(u, id);
    } else {
      nAns += d[id] + d[v] - d[di] * 2;
      pAns[++len] = make_pair(v, id);
    }
  }
}
int main() {
  int i, n;
  scanf("%d", &n);
  for (i = 1; i < n; i++) {
    scanf("%d%d", &u, &v);
    g[u].push_back(v);
    g[v].push_back(u);
  }
  dfsD(1, 0);
  for (i = u = 1; i <= n; i++)
    if (d[i] > d[u]) u = i;
  d[u] = 0;
  dfsD(u, 0);
  for (i = v = 1; i <= n; i++)
    if (d[i] > d[v]) v = i;
  for (i = v; i != u; i = rt[i]) dm[i] = true;
  dm[u] = true;
  dfs(u, u);
  for (i = v; i != u; i = rt[i]) {
    nAns += d[i];
    pAns[++len] = make_pair(u, i);
  }
  printf("%lld\n", nAns);
  for (i = 1; i <= len; i++)
    printf("%d %d %d\n", pAns[i].first, pAns[i].second, pAns[i].second);
  return 0;
}
