#include <bits/stdc++.h>
using namespace std;
bool flag[10005];
long long ans[10005];
int main() {
  int testCases, n, x, ind, k;
  vector<pair<int, pair<int, int> > > vec;
  vector<int> g;
  cin >> n;
  k = 2 * n;
  for (int i = 1; i < k; i++) {
    int temp = 0, j;
    for (j = 1; j <= i; j++) {
      cin >> x;
      vec.push_back(make_pair(x, make_pair(i + 1, j)));
    }
  }
  sort(vec.begin(), vec.end());
  k = vec.size();
  for (int i = k - 1; i >= 0; i--) {
    if (flag[vec[i].second.first] == false &&
        flag[vec[i].second.second] == false) {
      ans[vec[i].second.first] = vec[i].second.second;
      ans[vec[i].second.second] = vec[i].second.first;
      flag[vec[i].second.first] = true;
      flag[vec[i].second.second] = true;
    }
  }
  k = 2 * n;
  for (int i = 1; i <= k; i++) {
    cout << ans[i] << " ";
  }
  cout << endl;
  return 0;
}
