#include <bits/stdc++.h>
using namespace std;
vector<pair<int, pair<int, int> > > v;
int visited[801];
int main() {
  int n, i, x;
  cin >> n;
  int k = 2;
  for (i = 0; i < 2 * n - 1; i++) {
    for (int j = 1; j < k; j++)
      cin >> x, v.push_back(make_pair(x, make_pair(j, k)));
    k++;
  }
  sort(v.begin(), v.end());
  for (i = v.size() - 1; i >= 0; i--) {
    int x = v[i].second.first;
    int y = v[i].second.second;
    if (!visited[x] && !visited[y]) {
      visited[x] = y;
      visited[y] = x;
    }
  }
  for (i = 1; i <= 2 * n; i++) cout << visited[i] << " ";
  cout << endl;
  return 0;
}
