use strict;
use warnings;

my %nodes = (  A => 2,  B => 4,  C => 5, D => 1);
			
my @path = ("");
my @newpath;
	
foreach my $k (sort (keys(%nodes)))					# each level
{
	my @nodename;
	for (my $i = 1; $i <= $nodes{$k}; $i++)
	{
		push (@nodename, "$k$i");						   # generate node-names for each level
	}
	
	foreach my $old (@path)								# take all old paths
	{
		foreach my $new (@nodename)							# append new node to each
		{
			push (@newpath, "$old-$new");
		}
	}
	@path = @newpath;  										# save old paths
	@newpath  = ();										# clear list of new paths
}
print join("\n", @path);    # print all paths (each in a new line)
exit 0;