a-a a-b aaa aab aad aaf aah aar ab- aba abb abd abf abh abr ad- ada adb add adf adh adr af- afa afb afd aff afh afr aha ahb ahd ahf ahh ahr ar- ara arb ard arf arh arr baa bab bad baf bah bar bba bbb bbd bbf bbh bbr bda bdb bdd bdf bdh bdr bfa bfb bfd bff bfh bfr bha bhb bhd bhf bhh bhr bra brb brd brf brh brr daa dab dad daf dah dar dba dbb dbd dbf dbh dbr dda ddb ddd ddf ddh ddr dfa dfb dfd dff dfh dfr dh- dha dhb dhd dhf dhh dhr dra drb drd drr faa fab fad faf fah far fba fbb fbd fbf fbh fbr fda fdb fdd fdf fdh fdr ffa ffd fff ffh ffr fha fhb fhf fhh fhr fra frb frd frf frh frr haa hab had haf hah har hba hbb hbd hbf hbh hbr hda hdb hdd hdf hdh hdr hfa hfb hfd hff hfh hfr hha hhb hhd hhf hhh hhr hr- hra hrb hrd hrf hrh hrr ra- raa rab rad raf rah rar rba rbb rbd rbf rbh rbr rda rdb rdd rdf rdh rdr rfa rfb rfd rff rfh rfr rh- rha rhb rhd rhf rhh rhr rra rrb rrd rrf rrh rrr