#include <bits/stdc++.h>
const int MAXN = (int)1e5 + 5;
const int MODN = (int)1e9 + 7;
int inf = 0x3f3f3f3f;
using namespace std;
char str[MAXN];
int num[MAXN];
int a[MAXN];
int vis[MAXN];
int main() {
  int n, m;
  while (scanf("%d", &n) != EOF) {
    memset(vis, 0, sizeof(vis));
    int sum = 0;
    for (int i = 0; i < n; i++) {
      scanf("%d", &a[i]);
      sum += a[i];
    }
    int it = sum * 2 / n;
    for (int i = 0; i < n; i++) {
      if (vis[i] == 0) {
        vis[i] = 1;
        printf("%d ", i + 1);
        for (int j = 0; j < n; j++) {
          if (vis[j] == 0 && a[j] + a[i] == it) {
            vis[j] = 1;
            printf("%d\n", j + 1);
            break;
          }
        }
      }
    }
  }
}
