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