#include <iostream>
#include <algorithm>
#include <stdio.h>
#include <vector>
#include <queue>
using namespace std;


void smista(int N, int nemico[]) {

  freopen ("input.txt","r",stdin);
  freopen ("output.txt","w",stdout);
    int aQualeGruppo[N];
    bool can[N];
    for(int i = 0; i < N; i++)
    {
        aQualeGruppo[i] = -1; // la persona i appartiene al gruppo 0, 1, 2..
        can[N] = true;
    }

    int lastGroup = 0;
	int i;
	bool canCont = true;
	bool firstTime;

	while(canCont) {

	    canCont = false;
	    firstTime = true;
        for (i = 0; i < N; i++) {

  //     cout << " ------- " << endl;
    //    cout << aQualeGruppo[i] << ", " << aQualeGruppo[nemico[i]] << ", " << (can[i] ? "si" : "no") << endl;
       //cout << " f ---- f" << endl;
                if(aQualeGruppo[i] == -1 && aQualeGruppo[nemico[i]] != lastGroup && can[i])
                {
                    if(nemico[i] > i)
                        can[nemico[i]] = false;

                    aQualeGruppo[i] = lastGroup;
                    if(!firstTime)
                        cout << " ";
                    cout << i;
                    firstTime = false;
                }
                can[i] = true;

                if(aQualeGruppo[i] == -1)
                            canCont = true;
        }
        lastGroup++;

	if(canCont)
        cout << endl;
	}



}

int main1()
{


  freopen ("input.txt","r",stdin);
  freopen ("output.txt","w",stdout);

     int n;
     cin >> n;
     int nemico[n];

     for(int i = 0; i < n; i++)
        cin >> nemico[i];

    smista(n, nemico);

    return 0;
}