#include <bits/stdc++.h>
using namespace std;
int n, a[888][888], i, j, k, in[888], maxs, temp1, temp2;
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n;
  for (i = 2; i <= 2 * n; i++)
    for (j = 1; j <= i - 1; j++) cin >> a[i][j];
  for (k = 1; k <= n; k++) {
    maxs = 0;
    for (i = 2; i <= 2 * n; i++)
      for (j = 1; j <= i - 1; j++)
        if (maxs < a[i][j]) {
          maxs = a[i][j];
          temp1 = i;
          temp2 = j;
        }
    for (i = 2; i <= 2 * n; i++) {
      for (j = 1; j <= i - 1; j++)
        if (i == temp1 || i == temp2 || j == temp1 || j == temp2) a[i][j] = 0;
    }
    in[temp1] = temp2;
    in[temp2] = temp1;
  }
  for (i = 1; i <= 2 * n; i++) cout << in[i] << ' ';
}
