#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int i, j;
  static int a[1000][1000];
  for (i = 2; i <= 2 * n; i++) {
    for (j = 1; j < i; j++) {
      cin >> a[i][j];
      a[j][i] = a[i][j];
    }
  }
  int otv = 0;
  int res[1000];
  static int used[1000];
  int maxs[1000];
  int maxnum[1000];
  for (int k = 1; k <= n; k++) {
    for (i = 1; i <= 2 * n; i++) {
      if (used[i] == 0) {
        maxs[i] = 0;
        maxnum[i] = 0;
        for (j = 1; j <= 2 * n; j++) {
          if (a[i][j] > maxs[i] && used[j] == 0) {
            maxs[i] = a[i][j];
            maxnum[i] = j;
          }
        }
      }
    }
    for (i = 1; i <= 2 * n; i++) {
      if (maxnum[maxnum[i]] == i) {
        used[i] = 1;
        used[maxnum[i]] = 1;
        res[i] = maxnum[i];
        res[maxnum[i]] = i;
        otv++;
      }
    }
    if (otv == n) {
      break;
    }
  }
  for (i = 1; i <= 2 * n; i++) {
    cout << res[i] << ' ';
  }
}
