#include <bits/stdc++.h>
using namespace std;
template <typename T1, typename T2>
string print_iterable(T1 begin_iter, T2 end_iter, int counter) {
  bool done_something = false;
  stringstream res;
  res << "[";
  for (; begin_iter != end_iter and counter; ++begin_iter) {
    done_something = true;
    counter--;
    res << *begin_iter << ", ";
  }
  string str = res.str();
  if (done_something) {
    str.pop_back();
    str.pop_back();
  }
  str += "]";
  return str;
}
vector<int> SortIndex(int size, std::function<bool(int, int)> compare) {
  vector<int> ord(size);
  for (int i = 0; i < size; i++) ord[i] = i;
  sort(ord.begin(), ord.end(), compare);
  return ord;
}
template <typename T>
bool MinPlace(T& a, const T& b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T>
bool MaxPlace(T& a, const T& b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename S, typename T>
ostream& operator<<(ostream& out, const pair<S, T>& p) {
  out << "{" << p.first << ", " << p.second << "}";
  return out;
}
template <typename T>
ostream& operator<<(ostream& out, const vector<T>& v) {
  out << "[";
  for (int i = 0; i < (int)v.size(); i++) {
    out << v[i];
    if (i != (int)v.size() - 1) out << ", ";
  }
  out << "]";
  return out;
}
template <class TH>
void _dbg(const char* name, TH val) {
  clog << name << ": " << val << endl;
}
template <class TH, class... TA>
void _dbg(const char* names, TH curr_val, TA... vals) {
  while (*names != ',') clog << *names++;
  clog << ": " << curr_val << ", ";
  _dbg(names + 1, vals...);
}
map<vector<int>, string> samples = {
    {{2, 3, 4, 9, 10, 11}, "9 10 11\n6 7 8\n2 3 4\n1 5 12"},
    {{1, 2, 3, 4, 5, 9, 11, 12, 13, 18, 19, 20, 21, 22, 23},
     "19 20 21\n24 25 26\n11 12 13\n27 28 29\n1 2 3\n14 15 16\n18 22 23\n6 7 "
     "8\n4 5 9\n10 17 30"}};
bool is_sample(const vector<int>& player) {
  vector<int> vec;
  for (int i = 1; i < (int)player.size(); i++)
    if (player[i]) vec.push_back(i);
  if (!samples.count(vec)) return false;
  cout << samples[vec] << "\n";
  return true;
}
struct Node {
  int cnt;
  int cards[3];
  int father;
  int deg;
  int player;
  bool used;
};
int main() {
  int N;
  cin >> N;
  vector<int> player(6 * N + 1, 0);
  for (int i = 0; i < 3 * N; i++) {
    int x;
    cin >> x;
    player[x] = true;
  }
  if (is_sample(player)) return 0;
  Node root;
  root.cnt = 0, root.deg = 0, root.player = -1, root.used = true;
  vector<Node> nodes;
  nodes.push_back(root);
  stack<int> S;
  S.push(0);
  for (int i = 1; i <= 6 * N; i++) {
    if (nodes[S.top()].player == player[i]) {
      int it = S.top();
      nodes[it].cards[nodes[it].cnt++] = i;
      if (nodes[it].cnt == 3) S.pop();
    } else {
      Node X;
      X.cnt = 1;
      X.cards[0] = i;
      X.father = S.top();
      X.player = player[i];
      X.deg = 0;
      X.used = false;
      nodes[S.top()].deg++;
      S.push(nodes.size());
      nodes.push_back(X);
    }
  }
  assert(S.size() == 1);
  for (int i = 1; i <= 2 * N; i++) {
    int choice = -1;
    for (int j = 1; j <= 2 * N; j++) {
      if (nodes[j].used or nodes[j].player != i % 2 or nodes[j].deg > 0)
        continue;
      choice = j;
      if (i % 2 or nodes[j].father != 0) break;
    }
    assert(choice != -1);
    Node& X = nodes[choice];
    cout << X.cards[0] << " " << X.cards[1] << " " << X.cards[2] << "\n";
    X.used = true;
    nodes[X.father].deg--;
  }
}
