#include <bits/stdc++.h>
using namespace std;
set<pair<int, pair<int, int> > > S;
vector<int> visited(1001, 0);
vector<int> ans(1001);
int main() {
  int n, i, j, k;
  cin >> n;
  for (i = 1; i <= 2 * n; i++) {
    for (j = 1; j <= i - 1; j++) {
      int temp;
      cin >> temp;
      S.insert(make_pair(temp, make_pair(i, j)));
    }
  }
  set<pair<int, pair<int, int> > >::reverse_iterator it;
  int left = 2 * n;
  for (it = S.rbegin(); it != S.rend(); it++) {
    if (left == 0) break;
    int cost = (*it).first;
    int p1 = (*it).second.first;
    int p2 = (*it).second.second;
    if (visited[p1] == 0 and visited[p2] == 0) {
      left -= 2;
      ans[p1] = p2;
      ans[p2] = p1;
      visited[p1] = 1;
      visited[p2] = 1;
    }
  }
  for (i = 1; i <= 2 * n; i++) cout << ans[i] << " ";
  cout << endl;
  return 0;
}
