#include <bits/stdc++.h>
int person[1000001][2], an[1001];
bool used[1001];
int main() {
  int n;
  scanf("%d", &n);
  n *= 2;
  for (int i = 1; i <= n; i++)
    for (int j = 1; j < i; j++) {
      int x;
      scanf("%d", &x);
      person[x][0] = i;
      person[x][1] = j;
    }
  used[0] = 1;
  for (int i = 1000000; i > 0; i--) {
    if (!used[person[i][0]] && !used[person[i][1]]) {
      used[person[i][0]] = 1;
      used[person[i][1]] = 1;
      an[person[i][0]] = person[i][1];
      an[person[i][1]] = person[i][0];
    }
  }
  for (int i = 1; i <= n; i++) {
    if (i > 1) printf(" ");
    printf("%d", an[i]);
  }
  puts("");
  return 0;
}
