#include <bits/stdc++.h>
using namespace std;
long long a[100001], flag[100001];
vector<pair<long long, long long> > ans;
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n, sum = 0;
  cin >> n;
  for (long long i = 0; i < n; i++) {
    cin >> a[i];
    sum += a[i];
  }
  sum /= n / 2;
  for (long long i = 0; i < n; i++) {
    if (flag[i] == 0)
      for (long long j = i + 1; j < n; j++) {
        if (flag[j] == 0 && ((a[i] + a[j]) == sum)) {
          flag[j] = 1;
          flag[i] = 1;
          ans.push_back(make_pair(i + 1, j + 1));
          break;
        }
      }
  }
  for (auto i : ans) {
    cout << i.first << " " << i.second << endl;
  }
  return 0;
}
