#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n;
  cin >> n;
  vector<pair<long long, pair<long long, long long> > > v;
  for (long long i = 2; i <= 2 * n; ++i) {
    for (long long j = 1; j < i; ++j) {
      long long x;
      cin >> x;
      v.push_back({x, {i, j}});
    }
  }
  sort(v.begin(), v.end(),
       greater<pair<long long, pair<long long, long long> > >());
  vector<long long> vv(999, 0);
  for (long long i = 0; i < (long long)v.size(); ++i) {
    long long x = v[i].second.first;
    long long y = v[i].second.second;
    if (vv.at(x) == 0 && vv.at(y) == 0) {
      vv.at(x) = y;
      vv.at(y) = x;
    }
  }
  for (long long i = 1; i <= 2 * n; ++i) {
    cout << vv.at(i) << " ";
  }
  cout << "\n";
  return 0;
}
