#include <bits/stdc++.h>
using namespace std;
const int N = 200010;
struct edge {
  int y, nex;
} s[N << 1];
int first[N], len = 0, n, mx, p;
int a[N], tot, t;
pair<int, int> ans[N];
long long op = 0;
void ins(int x, int y) {
  s[++len] = (edge){y, first[x]};
  first[x] = len;
}
void dfs(int x, int fa, int dep) {
  if (dep > mx) mx = dep, p = x;
  for (int i = first[x]; i != 0; i = s[i].nex)
    if (s[i].y != fa) dfs(s[i].y, x, dep + 1);
}
void ga(int x, int tar, int fa) {
  if (x == tar) {
    a[++tot] = tar;
    return;
  }
  for (int i = first[x]; i; i = s[i].nex)
    if (s[i].y != fa) {
      ga(s[i].y, tar, x);
      if (tot) {
        a[++tot] = x;
        return;
      }
    }
}
void gas(int x, int fa, int pos, int dep) {
  for (int i = first[x]; i; i = s[i].nex)
    if (s[i].y != fa) gas(s[i].y, x, pos, dep + 1);
  op += dep;
  ans[++t] = make_pair(pos, x);
}
int main() {
  scanf("%d", &n);
  int x, y;
  for (int i = 1; i < n; i++) scanf("%d %d", &x, &y), ins(x, y), ins(y, x);
  mx = 0;
  dfs(1, 0, 0);
  mx = 0;
  x = p;
  dfs(p, 0, 0);
  ga(x, p, 0);
  for (int i = 1; i <= tot; i++) {
    for (int j = first[a[i]]; j; j = s[j].nex)
      if (s[j].y != a[i - 1] && s[j].y != a[i + 1])
        gas(s[j].y, a[i], i <= tot / 2 ? a[tot] : a[1], max(i, tot - i + 1));
  }
  printf("%lld\n", op + 1ll * tot * (tot - 1) / 2);
  for (int i = 1; i <= t; i++)
    printf("%d %d %d\n", ans[i].first, ans[i].second, ans[i].second);
  for (int i = 1; i <= tot - 1; i++) printf("%d %d %d\n", a[tot], a[i], a[i]);
}
