#include <bits/stdc++.h>
using namespace std;
struct edge {
  int to, next;
} e[200005 * 2];
int d[200005], dl[200005], dr[200005], dd[200005];
int head[200005], q[200005], id[200005], a[200005];
long long ans;
int n, tot;
bool cmp(int x, int y) {
  if (dd[x] != dd[y]) return dd[x] > dd[y];
  return dl[x] > dl[y];
}
void add(int x, int y) {
  e[++tot] = (edge){y, head[x]};
  head[x] = tot;
}
void bfs(int S, int *d) {
  for (int i = 1; i <= n; i++) d[i] = -1;
  d[S] = 0;
  q[1] = S;
  for (int h = 0, t = 1; h != t;)
    for (int x = q[++h], i = head[x]; i; i = e[i].next)
      if (d[e[i].to] == -1) d[e[i].to] = d[x] + a[e[i].to], q[++t] = e[i].to;
}
int findmax(int *d) {
  int mx = 1;
  for (int i = 2; i <= n; i++)
    if (d[mx] < d[i]) mx = i;
  return mx;
}
int main() {
  scanf("%d", &n);
  for (int i = 1; i < n; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    add(x, y);
    add(y, x);
  }
  for (int i = 1; i <= n; i++) a[i] = 1;
  bfs(1, d);
  int l = findmax(d);
  bfs(l, dl);
  int r = findmax(dl);
  bfs(r, dr);
  for (int i = 1; i <= n; i++)
    if (dl[i] + dr[i] == dl[r])
      a[i] = 0;
    else
      ans += max(dl[i], dr[i]);
  ans += 1ll * dl[r] * (dl[r] + 1) / 2;
  printf("%I64d\n", ans);
  bfs(l, dd);
  for (int i = 1; i <= n; i++) id[i] = i;
  sort(id + 1, id + n + 1, cmp);
  for (int i = 1; i < n; i++)
    if (dd[id[i]]) {
      int tmp = dl[id[i]] > dr[id[i]] ? l : r;
      printf("%d %d %d\n", tmp, id[i], id[i]);
    } else
      printf("%d %d %d\n", l, id[i], id[i]);
}
