#include <bits/stdc++.h>
using namespace std;
class obj {
 public:
  int fst;
  int snd;
  int weight;
};
bool operator<(obj a, obj b) {
  if (a.weight != b.weight) return a.weight > b.weight;
  return false;
}
vector<obj> v;
int players[1010];
void solve() {
  sort(v.begin(), v.end());
  for (int i = 0; i < v.size(); i++) {
    int f_player = v[i].fst;
    int s_player = v[i].snd;
    if (players[f_player] || players[s_player]) {
      continue;
    }
    players[f_player] = s_player;
    players[s_player] = f_player;
  }
}
void print(int n) {
  for (int i = 1; i <= (2 * n); i++) {
    if (i == 1)
      cout << players[i];
    else
      cout << " " << players[i];
  }
  cout << endl;
}
int main() {
  int n;
  cin >> n;
  obj tmp;
  int curw = 0;
  for (int i = 1; i < (2 * n); i++) {
    for (int j = 0; j < i; j++) {
      scanf("%d", &curw);
      tmp.fst = i + 1;
      tmp.snd = j + 1;
      tmp.weight = curw;
      v.push_back(tmp);
    }
  }
  solve();
  print(n);
  return 0;
}
