#include <bits/stdc++.h>
using namespace std;
constexpr int MAXN = 1e3 + 15, MAXN2 = 1e6 + 15;
long long n, a[MAXN], c[MAXN], b[MAXN2][3], t;
int main() {
  cin >> n;
  for (int i = 1; i < 2 * n; i++)
    for (int j = 0; j < i; j++)
      cin >> t, t--, b[t][0] = 1, b[t][1] = i, b[t][2] = j, a[i] = 1, a[j] = 1;
  for (int i = MAXN2 - 15; i >= 0; i--)
    if (b[i][0] == 1 && a[b[i][1]] == 1 && a[b[i][2]] == 1)
      a[b[i][1]] = 0, a[b[i][2]] = 0, c[b[i][1]] = b[i][2],
      c[b[i][2]] = b[i][1];
  for (int i = 0; i < 2 * n; i++) cout << c[i] + 1 << ' ';
  return false;
}
