use strict;
use warnings;
use Data::Dumper;

my $pt = { value => "D", next => undef }; 
my $pt2 = {value => "C", next => $pt};
$pt = {value => "B", next => $pt2};
my $L = { value => "A", next => $pt};

sub solution {
    my $list = shift;
    my $length = 0;
    while (1) {
	    return $length unless defined $list->{value}; # added for the case of an empty list
	    print $list->{value};
	    $length++;
	    return $length unless defined $list->{next};
	    $list = $list->{next};
    }
}
    
my $len = solution($L);
print "\n$len \n";

print Dumper $L;