#!/usr/bin/perl

use strict;
use warnings;
#
my @CS_CHECKS = ( '00012345', 'D123470', '0000123450', '0000023456', '50000123990' );
my @B_CHECKS = ( '1234', '12345', '123990', '12399' );
my %seen;
for my $cn ( @CS_CHECKS )
{
    for my $bn ( @B_CHECKS )
    {
        if ( $cn =~ /^(0|5|6)0+\Q$bn\E$/ )
        {
            print "$bn = $cn\n";
        }
    }

}