#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1.0);
const int inf = 0x3f3f3f3f;
const double eps = 1e-15;
const long long INF = (1LL << 60);
int mat[1044][1044];
bool use[1044];
int arr[1044];
int main() {
  int n;
  scanf("%d", &n);
  memset(use, 0, sizeof(use));
  for (int i = 2; i <= 2 * n; ++i) {
    for (int j = 1; j < i; ++j) {
      scanf("%d", &mat[i][j]);
    }
  }
  while (1) {
    int val = -1, id1, id2;
    for (int i = 2; i <= 2 * n; ++i) {
      if (use[i]) {
        continue;
      }
      for (int j = 1; j < i; ++j) {
        if (!use[j] && mat[i][j] > val) {
          val = mat[i][j];
          id1 = i, id2 = j;
        }
      }
    }
    if (val == -1) {
      break;
    }
    use[id1] = use[id2] = 1;
    arr[id1] = id2;
    arr[id2] = id1;
  }
  for (int i = 1; i <= 2 * n; ++i) {
    printf("%d", arr[i]);
    if (i < 2 * n) {
      printf(" ");
    }
  }
  printf("\n");
  return 0;
}
