#!/usr/bin/php
<?php

$input = stream_get_contents(STDIN);

$input = explode("\n", $input);

for ($j = 0, $max = sizeof($input); $j < $max; $j += 2)
{
        if (intval($input[$j]) == 0)
        {
                exit;
        }

        $n = intval($input[$j]);

        preg_match_all('/-?\d+/', $input[$j + 1], $b_raw, PREG_PATTERN_ORDER);

        $b = array_combine(range(1, sizeof($b_raw[0])), $b_raw[0]);
        $a = array_combine(range(1, sizeof($b_raw[0])), array_fill(1, sizeof($b_raw[0]), 0));

        $stack = range($n, 1);

        if (sizeof($b) !== $n)
        {
                echo '-1', "\n";
        }

        foreach ($b as $i => $value)
        {
                $a[$i] = intval(implode('', array_splice($stack, $b[$i], 1)));
        }

        echo ((empty($stack)) ? implode(' ', $a) : '-1'), "\n";
/*
print_r($a);
print_r($b);
print_r($stack);
//*/
}
?>