#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, mx = 0, id;
  cin >> n;
  vector<pair<long long int, pair<long long int, long long int> > > v;
  vector<long long int> ans(2 * n + 9), ha(1000, 0);
  for (long long int i = 2; i <= 2 * n; i++) {
    for (long long int j = 1; j <= i - 1; j++) {
      long long int x;
      cin >> x;
      v.push_back({x, {i, j}});
    }
  }
  sort((v).begin(), (v).end());
  for (long long int i = v.size() - 1; i >= 0; i--) {
    long long int a = v[i].second.first, b = v[i].second.second;
    if (ha[a] == 0 && ha[b] == 0) {
      ans[a] = b;
      ans[b] = a;
      ha[a]++;
      ha[b]++;
    }
  }
  for (long long int i = 1; i <= 2 * n; i++) {
    cout << ans[i] << " ";
  }
}
