#include <bits/stdc++.h>
using namespace std;
const int maxn = 401;
int a[2 * maxn][2 * maxn];
int vis[2 * maxn];
int main() {
  int n;
  while (cin >> n) {
    memset(vis, 0, sizeof(vis));
    memset(a, 0, sizeof(a));
    for (int i = 2; i <= 2 * n; i++)
      for (int j = 1; j <= i - 1; j++) scanf("%d", &a[i][j]);
    int cnt = 0;
    while (1) {
      int mx = 0, k, h;
      for (int i = 2; i <= 2 * n; i++) {
        for (int j = 1; j <= i - 1; j++) {
          if (a[i][j] > mx && !vis[i] && !vis[j]) {
            k = i;
            h = j;
            mx = a[i][j];
          }
        }
      }
      vis[k] = h;
      vis[h] = k;
      cnt++;
      cnt++;
      if (cnt == 2 * n) break;
    }
    for (int i = 1; i <= 2 * n; i++) {
      if (i == 2 * n)
        cout << vis[i] << endl;
      else
        cout << vis[i] << " ";
    }
  }
  return 0;
}
