#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <vector>

using namespace std;

int main()
{
    int n,i,meio,inicio,fim;

    cin>>n;

    vector< pair<int,int> >vet;

    int aux;
    for(i=0;i<n;i++){
        cin>>aux;

        vet.push_back(make_pair(aux,i+1));

    }

    meio = n / 2;
    inicio = 0;
    fim = n-1;

    sort(vet.begin(),vet.end());

    i = 0;
    int j = 0;
    bool f = false;

    for(i=0;i<n-1;i++){

        if(vet[i]!=vet[i+1]){

            f = true;
            break;
        }

    }

        while(inicio <= meio && fim >= meio){

            printf("%d %d",vet[inicio].second,vet[fim].second);

            printf("\n");

            inicio++;
            fim--;
        }

    return 0;
}