Codewords:

Level 2           HBBT       Level 11       TRNS
Level 3           PCRC       Level 12       RNSN
Level 4           NWTN       Level 13       ZDCP
Level 5           LSMD       Level 14       FKDV
Level 6           CLST       Level 15       YSHM
Level 7           JPTR       Level 16       CLPD
Level 8           NBLR       Level 17       LNVV
Level 9           PRSC       Level 18       JFMR
Level 10    PHTN       Level 19       JCRY
                     Level 20       KNLB

Codewords contributed by Arne Beilschmidt - Beilschmidt@t-online.de