#!/usr/bin/perl -w
use strict;

my $hint = '1234';
my @chars = ('0'..'9', 'a'..'z');
my $len = 6 - length $hint;

&append ("");

sub append {
        my $s = shift;


        if (length $s >= $len) {
                &hint($s);
                return;
        }
        foreach (@chars) {
                my $new = $s.$_;
                &append ($new);
        }
}

sub hint {
        my $s = shift;
        my $new;
        for (my $i=0; $i<=length($s); ++$i) {
                $s =~ m/^(.{$i})(.*)$/;
                $new = $1.$hint.$2;
                print $new."\n";
        }
}