#include <bits/stdc++.h>
int arr[1000001][2];
int ans[800];
int main() {
  int N, cnt;
  int i, j, in, max = 0, min = 1000001;
  scanf("%d", &N);
  N *= 2;
  ans[0] = -1;
  for (i = 1; i < N; i++) {
    for (j = 0; j < i; j++) {
      scanf("%d", &in);
      arr[in][0] = i;
      arr[in][1] = j;
      max = max > in ? max : in;
      min = min < in ? min : in;
    }
    ans[i] = -1;
  }
  cnt = 0;
  for (i = max; i >= min && cnt != N; i--) {
    if (arr[i][0] != arr[i][1])
      if (ans[arr[i][0]] == -1 && ans[arr[i][1]] == -1) {
        ans[arr[i][0]] = arr[i][1];
        ans[arr[i][1]] = arr[i][0];
        cnt++;
      }
  }
  for (i = 0; i < N; i++) printf("%d ", ans[i] + 1);
  return 0;
}
