#include <algorithm>
#include <array>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <ostream>
#include<complex>
#include <cmath>
#include <iostream>
#include <stack>
#include <fstream>
#include <queue>
#include <list>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <bitset>
#include <iomanip>
#include <string>
#include <vector>
#include <string>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define ALLOF(c) (c),begin(), (c),end()
typedef long long ll;


int main()
{ 
    int n;
    int a[50];
    int allow_count[50];
    int dispatched[50];
    bool end[50];
    cin >> n;
    fill(dispatched,dispatched + 50, -1);
    fill(allow_count,allow_count+50, n);
    fill(end,end+50,false);
    rep(i,n)
    {
        cin >> a[i];
    }
    rep(i,n)
    {
        allow_count[a[i]]--;
    }
    rep(i,n)
    {
        if(allow_count[i] == 0)
        {
            cout << -1 << endl;
            return 0;
        }        
    }
    rep(i,n)
    {
        int need_dispatch = 0;
        int tmp_c = n+1;
        rep(j,n)
        {
            if ( !end[j] && tmp_c > allow_count[j])
            {

                need_dispatch = j;
                tmp_c = allow_count[j];
            }
        }

#ifdef _DEBUG
        cout << tmp_c << "  " << need_dispatch << endl;
#endif _DEBUG      

        rep(j,n)
        {
            if (dispatched[j] == -1 && a[j] != need_dispatch)
            {

#ifdef _DEBUG
                cout << "dispatched" << need_dispatch <<" in" << j << endl;
#endif _DEBUG      

                dispatched[j] = need_dispatch;
                allow_count[need_dispatch]++;//あとで全部引くのでプラマイ0補正
                end[need_dispatch] = true; 
                break;
            }
        }
        rep(j,n)
        {
            allow_count[j]--;
        }
    }
    rep(i,n)
    {
        cout << dispatched[i] << endl;
    }
    return 0;
}