#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using db = double;
using str = string;
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
template <class T>
using V = vector<T>;
template <class T, size_t SZ>
using AR = array<T, SZ>;
const int MOD = 1e9 + 7;
const int MX = 2e5 + 5;
const ll INF = 1e18;
const ld PI = acos((ld)-1);
const int xd[4] = {1, 0, -1, 0}, yd[4] = {0, 1, 0, -1};
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());
constexpr int pct(int x) { return __builtin_popcount(x); }
constexpr int bits(int x) { return 31 - __builtin_clz(x); }
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); }
ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); }
template <class T>
bool ckmin(T& a, const T& b) {
  return b < a ? a = b, 1 : 0;
}
template <class T>
bool ckmax(T& a, const T& b) {
  return a < b ? a = b, 1 : 0;
}
template <class T, class U>
T fstTrue(T lo, T hi, U first) {
  hi++;
  assert(lo <= hi);
  while (lo < hi) {
    T mid = lo + (hi - lo) / 2;
    first(mid) ? hi = mid : lo = mid + 1;
  }
  return lo;
}
template <class T, class U>
T lstTrue(T lo, T hi, U first) {
  lo--;
  assert(lo <= hi);
  while (lo < hi) {
    T mid = lo + (hi - lo + 1) / 2;
    first(mid) ? lo = mid : hi = mid - 1;
  }
  return lo;
}
template <class T>
void remDup(vector<T>& v) {
  sort(begin(v), end(v));
  v.erase(unique(begin(v), end(v)), end(v));
}
template <class T, class U>
void erase(T& t, const U& u) {
  auto it = t.find(u);
  assert(it != end(t));
  t.erase(u);
}
template <class T>
void re(complex<T>& c);
template <class T, class U>
void re(pair<T, U>& p);
template <class T>
void re(vector<T>& v);
template <class T, size_t SZ>
void re(AR<T, SZ>& a);
template <class T>
void re(T& x) {
  cin >> x;
}
void re(db& d) {
  str t;
  re(t);
  d = stod(t);
}
void re(ld& d) {
  str t;
  re(t);
  d = stold(t);
}
template <class T, class... U>
void re(T& t, U&... u) {
  re(t);
  re(u...);
}
template <class T>
void re(complex<T>& c) {
  T a, b;
  re(a, b);
  c = {a, b};
}
template <class T, class U>
void re(pair<T, U>& p) {
  re(p.first, p.second);
}
template <class T>
void re(vector<T>& x) {
  for (auto& a : x) re(a);
}
template <class T, size_t SZ>
void re(AR<T, SZ>& x) {
  for (auto& a : x) re(a);
}
str to_string(char c) { return str(1, c); }
str to_string(const char* second) { return (str)second; }
str to_string(str second) { return second; }
str to_string(bool b) { return to_string((int)b); }
template <class T>
str to_string(complex<T> c) {
  stringstream ss;
  ss << c;
  return ss.str();
}
str to_string(vector<bool> v) {
  str res = "{";
  for (int i = (0); i < ((int)(v).size()); ++i) res += char('0' + v[i]);
  res += "}";
  return res;
}
template <size_t SZ>
str to_string(bitset<SZ> b) {
  str res = "";
  for (int i = (0); i < (SZ); ++i) res += char('0' + b[i]);
  return res;
}
template <class T, class U>
str to_string(pair<T, U> p);
template <class T>
str to_string(T v) {
  bool fst = 1;
  str res = "";
  for (const auto& x : v) {
    if (!fst) res += " ";
    fst = 0;
    res += to_string(x);
  }
  return res;
}
template <class T, class U>
str to_string(pair<T, U> p) {
  return to_string(p.first) + " " + to_string(p.second);
}
template <class T>
void pr(T x) {
  cout << to_string(x);
}
template <class T, class... U>
void pr(const T& t, const U&... u) {
  pr(t);
  pr(u...);
}
void ps() { pr("\n"); }
template <class T, class... U>
void ps(const T& t, const U&... u) {
  pr(t);
  if (sizeof...(u)) pr(" ");
  ps(u...);
}
void DBG() { cerr << "]" << endl; }
template <class T, class... U>
void DBG(const T& t, const U&... u) {
  cerr << to_string(t);
  if (sizeof...(u)) cerr << ", ";
  DBG(u...);
}
void setIn(str second) { freopen(second.c_str(), "r", stdin); }
void setOut(str second) { freopen(second.c_str(), "w", stdout); }
void unsyncIO() { cin.tie(0)->sync_with_stdio(0); }
void setIO(str second = "") {
  unsyncIO();
  if ((int)(second).size()) {
    setIn(second + ".in"), setOut(second + ".out");
  }
}
int n;
vi x;
int cool[1200][1200];
int col[1200];
bool get(int l, int r) {
  if (l > r) return 1;
  return cool[l][r];
}
V<AR<int, 3>> trip[2];
const AR<int, 3> ID = {-1, -1, -1};
bool lef[1200];
int nex[1200];
bool match(int a, pi b) {
  if (b.first > b.second) return 0;
  return col[a] == col[b.first];
}
bool ok[1201][2];
pi pre[1201][2];
bool rooted[1201];
void oops(int i, int j) {
  if (col[i] != col[j]) return;
  for (int k = i + 2; k < j; k += 3)
    if (col[k] == col[k + 1]) cool[i][j] |= get(i, k) & get(k + 1, j);
  for (int k = i + 1; k < j; k += 3)
    if (col[i] == col[k] && !match(i, {i + 1, k - 1}) &&
        !match(i, {k + 1, j - 1}))
      cool[i][j] |= get(i + 1, k - 1) & get(k + 1, j - 1);
}
void gen(int i, int j, int start = 0) {
  if (i > j) return;
  assert(cool[i][j] && col[i] == col[j]);
  for (int k = i + 2; k < j; k += 3)
    if (col[k] == col[k + 1])
      if (get(i, k) && get(k + 1, j)) {
        assert(!start);
        gen(i, k);
        gen(k + 1, j);
        return;
      }
  for (int k = i + 1; k < j; k += 3)
    if (col[i] == col[k] && !match(i, {i + 1, k - 1}) &&
        !match(i, {k + 1, j - 1}))
      if (get(i + 1, k - 1) && get(k + 1, j - 1)) {
        trip[col[i]].push_back({i, k, j});
        gen(i + 1, k - 1);
        gen(k + 1, j - 1);
        return;
      }
  assert(0);
}
int main() {
  setIO();
  re(n);
  x.resize(3 * n);
  re(x);
  for (int i = (0); i < (6 * n); ++i) col[i] = 1;
  for (auto& t : x) {
    t--;
    col[t] = 0;
  }
  for (int i = (6 * n) - 1; i >= (0); --i)
    for (int j = i + 2; j < 6 * n; j += 3) {
      oops(i, j);
    }
  ok[0][0] = 1;
  for (int i = (0); i < (6 * n); ++i)
    for (int p = (0); p < (2); ++p)
      if (ok[i][p])
        for (int j = (i + 1); j < (6 * n + 1); ++j)
          if (cool[i][j - 1]) {
            int P = p | col[i];
            ok[j][P] = 1;
            pre[j][P] = {i, p};
          }
  assert(ok[6 * n][1]);
  vi ends;
  pi cur = {6 * n, 1};
  while (cur.first) {
    ends.push_back(cur.first);
    cur = pre[cur.first][cur.second];
  }
  ends.push_back(0);
  reverse(begin(ends), end(ends));
  for (int i = (0); i < ((int)(ends).size() - 1); ++i)
    gen(ends[i], ends[i + 1] - 1, 1);
  for (auto& t : ends) rooted[t] = 1;
  for (int j = (0); j < (6 * n); ++j) lef[j] = 1;
  for (int i = (0); i < (2 * n); ++i) {
    int lst = -1;
    for (int j = (0); j < (6 * n); ++j)
      if (lef[j]) {
        if (lst != -1) nex[lst] = j;
        lst = j;
      }
    AR<int, 3> test = ID;
    for (auto& t : trip[i & 1])
      if (nex[t[0]] == t[1] && nex[t[1]] == t[2] && !rooted[t[0]]) test = t;
    if (test == ID) {
      for (auto& t : trip[i & 1])
        if (nex[t[0]] == t[1] && nex[t[1]] == t[2] && rooted[t[0]]) test = t;
    }
    assert(test != ID);
    trip[i & 1].erase(find(begin(trip[i & 1]), end(trip[i & 1]), test));
    lef[test[0]] = lef[test[1]] = lef[test[2]] = 0;
    ps(test[0] + 1, test[1] + 1, test[2] + 1);
  }
}
