#include <bits/stdc++.h>
using namespace std;
int finans[1000];
int fbdn[1000];
int mat[800][800];
int main(int argc, char const *argv[]) {
  int n;
  cin >> n;
  for (int i = 2; i <= 2 * n; i++) {
    for (int j = 1; j < i; j++) cin >> mat[i][j];
  }
  for (int k = 1; k <= n; k++) {
    int maxx = 0;
    int x, y;
    for (int i = 2; i <= 2 * n; i++) {
      for (int j = 1; j < i; j++) {
        if (mat[i][j] > maxx) {
          x = i;
          y = j;
          maxx = mat[i][j];
        }
      }
    }
    finans[x] = y;
    finans[y] = x;
    for (int i = 1; i <= 2 * n; i++) {
      mat[x][i] = -1;
      mat[i][x] = -1;
      mat[y][i] = -1;
      mat[i][y] = -1;
    }
  }
  for (int i = 1; i <= 2 * n; i++) cout << finans[i] << " ";
}
