#include <bits/stdc++.h>
using namespace std;
int arr[1000001][4];
int main() {
  int N, x, team[1001] = {0};
  scanf("%d", &N);
  for (int i = 1; i <= 2 * N; i++) {
    for (int j = 1; j < i; j++) {
      scanf("%d", &x);
      arr[x][0] = i;
      arr[x][1] = j;
    }
  }
  for (int i = 1000000; i > 0; i--) {
    if (team[arr[i][0]] == 0 && team[arr[i][1]] == 0) {
      team[arr[i][0]] = arr[i][1];
      team[arr[i][1]] = arr[i][0];
    }
  }
  for (int i = 1; i <= 2 * N; i++) printf("%d ", team[i]);
  return 0;
}
