#include <bits/stdc++.h>
using namespace std;
long long mod = 1000000007;
using namespace std;
int mark[1000], ans[1000];
vector<pair<int, pair<int, int> > > v;
int main() {
  int n;
  scanf("%d", &n);
  ;
  for (int i = 2; i <= 2 * n; i++) {
    for (int j = 1; j < i; j++) {
      int temp;
      scanf("%d", &temp);
      ;
      v.push_back(make_pair(temp, make_pair(i, j)));
    }
  }
  sort(v.begin(), v.end());
  for (int i = v.size() - 1; i >= 0; i--) {
    int p = v[i].second.first;
    int q = v[i].second.second;
    if (!mark[p] && !mark[q]) {
      ans[p] = q;
      ans[q] = p;
      mark[p] = 1;
      mark[q] = 1;
    }
  }
  for (int i = 1; i <= 2 * n; i++) {
    printf("%d ", ans[i]);
  }
  cout << endl;
  return 0;
}
