#include <bits/stdc++.h>
using namespace std;
int n;
vector<pair<int, pair<int, int>>> v;
int fri[1000];
bool taken[1000];
int main() {
  cin >> n;
  for (int i = 2; i <= 2 * n; i++) {
    for (int j = 1; j <= i - 1; j++) {
      int x;
      cin >> x;
      v.push_back({x, {i, j}});
    }
  }
  sort(v.rbegin(), v.rend());
  for (int i = 0; i < (int)v.size(); i++) {
    int p1 = v[i].second.first, p2 = v[i].second.second;
    if (!taken[p1] and !taken[p2]) {
      fri[p1] = p2;
      fri[p2] = p1;
      taken[p1] = taken[p2] = 1;
    }
  }
  for (int i = 1; i <= 2 * n; i++) cout << fri[i] << ' ';
}
