#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  vector<pair<int, pair<int, int>>> v;
  int a;
  for (int i = 2; i <= 2 * n; i++) {
    for (int j = 1; j < i; j++) {
      cin >> a;
      v.push_back(make_pair(a, make_pair(i, j)));
    }
  }
  int array[200007];
  memset(array, 0, sizeof(array));
  sort(v.begin(), v.end());
  int arr[200007];
  int x, y;
  int r = v.size();
  x = v[r - 1].second.first;
  y = v[r - 1].second.second;
  array[x] = 1;
  array[y] = 1;
  arr[y] = x;
  arr[x] = y;
  for (int i = r - 2; i >= 0; i--) {
    x = v[i].second.second;
    y = v[i].second.first;
    if (array[x] == 1 || array[y] == 1) {
      continue;
    }
    {
      array[y] = 1;
      array[x] = 1;
      arr[y] = x;
      arr[x] = y;
    }
  }
  for (int i = 1; i <= 2 * n; i++) {
    cout << arr[i] << " ";
  }
  return 0;
}
