#include <bits/stdc++.h>
using namespace std;
long long n, a[801][801], ma = -1, ini, inj, c[801];
bool b[801];
int main() {
  cin >> n;
  for (long long i = 1; i < 2 * n; i++) {
    for (long long j = 0; j < i; j++) {
      cin >> a[i][j];
    }
  }
  for (long long i = 0; i < n; i++) {
    ma = -1;
    for (long long i = 1; i < 2 * n; i++) {
      for (long long j = 0; j < i; j++) {
        if ((!b[i] && !b[j]) && (a[i][j] > ma)) {
          ma = a[i][j];
          ini = i;
          inj = j;
        }
      }
    }
    b[ini] = true;
    b[inj] = true;
    c[ini] = inj + 1;
    c[inj] = ini + 1;
  }
  for (long long i = 0; i < 2 * n; i++) {
    cout << c[i] << " ";
  }
  return 0;
}
