[ Bonn ] --> [ Ulm ]
[ Bonn ] --> [ Berlin ]
[ Bonn ] --> [ Koblenz ]
[ Berlin ] --> [ Kassel ]
[ Koblenz ] --> [ Berlin ]
[ Ulm ] --> [ Bautzen ]
[ Ulm ] --> [ Bautzen ]
[ Ulm ] --> [ Koblenz ]
[ Bautzen ] --> [ Berlin ]
[ Bautzen ] --> [ Berlin ]
