#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  map<int, int> m;
  vector<pair<int, pair<int, int> > > v;
  int x, var[2 * n + 1];
  for (int i = 2, k = 0; i <= 2 * n; i++, k++) {
    var[k] = 0;
    for (int j = 1; j <= i - 1; j++) {
      cin >> x;
      v.push_back(make_pair(x, make_pair(j, i)));
    }
  }
  sort(v.rbegin(), v.rend());
  for (int i = 0; i < v.size(); i++) {
    if (var[v[i].second.second] != 1 && var[v[i].second.first] != 1) {
      m[v[i].second.first] = v[i].second.second;
      m[v[i].second.second] = v[i].second.first;
      var[v[i].second.first] = var[v[i].second.second] = 1;
    }
  }
  for (int i = 1; i <= 2 * n; i++) cout << m[i] << " ";
  cout << endl;
  return 0;
}
