#include <bits/stdc++.h>
using namespace std;
const int N = 2410;
int n, l, r, a[N];
vector<int> p;
tuple<int, int, int> tmp[2];
vector<tuple<int, int, int>> ans;
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n;
  for (int i = 1, x; i <= 3 * n; i++) cin >> x, a[x] = 1;
  for (int i = 1; i <= 6 * n; i++) p.push_back(i);
  for (int i = 1; i <= 2 * n; i++) {
    l = 0, r = p.size() - 1;
    while (l < r && a[p[l]] == a[p[l + 1]] && a[p[l]] == a[p[l + 2]])
      tmp[a[p[l]]] = {p[l], p[l + 1], p[l + 2]}, l += 3;
    while (l < r && a[p[r]] == a[p[r - 1]] && a[p[r]] == a[p[r - 2]])
      tmp[a[p[r]]] = {p[r - 2], p[r - 1], p[r]}, r -= 3;
    if (l < r) {
      for (int j = l; j + 2 <= r; j++)
        if ((i & 1) == a[p[j]] && (i & 1) == a[p[j + 1]] &&
            (i & 1) == a[p[j + 2]]) {
          ans.push_back({p[j], p[j + 1], p[j + 2]});
          goto next;
        }
    }
    ans.push_back(tmp[i & 1]);
  next:
    p.erase(find(p.begin(), p.end(), get<0>(ans.back())));
    p.erase(find(p.begin(), p.end(), get<1>(ans.back())));
    p.erase(find(p.begin(), p.end(), get<2>(ans.back())));
  }
  for (const auto &it : ans)
    cout << get<0>(it) << " " << get<1>(it) << " " << get<2>(it) << endl;
}
