#include <bits/stdc++.h>
using namespace std;
const double error = 1e-15;
const double pi = 2 * acos(0);
const int maxn = (int)1e5 + 10;
const int mod = (int)1e9;
int dx[] = {0, -1, 0, +1, -1, -1, +1, +1};
int dy[] = {-1, 0, +1, 0, -1, +1, +1, -1};
long int A[900], B[900], C[900];
vector<pair<long, pair<int, int> > > v;
int main() {
  ios_base::sync_with_stdio(0);
  long n, i, j, x;
  cin >> n;
  for (i = 2; i <= 2 * n; i++) {
    for (j = 1; j < i; j++) {
      cin >> x;
      v.push_back(make_pair(x, make_pair(i, j)));
    }
  }
  sort(v.begin(), v.end());
  x = v.size();
  for (i = x - 1; i >= 0; i--)
    if (A[v[i].second.first] == 0 && A[v[i].second.second] == 0) {
      C[v[i].second.first] = v[i].second.second;
      C[v[i].second.second] = v[i].second.first;
      A[v[i].second.first] = 1;
      A[v[i].second.second] = 1;
    }
  for (i = 1; i <= 2 * n; i++) cout << C[i] << " ";
  return 0;
}
