a-a a-b a-c aaa aab aac aah aan aao aas ab- aba abb abc abh abn abo abs ac- aca acb acc ach acn aco acs aha ahb ahc ahh ahn aho ahs an- ana anb anc anh ann ano ans aoa aob aoc aoh aon aoo aos as- asa asb asc ash asn aso ass baa bab bac bah ban bao bas bba bbb bbc bbh bbn bbo bbs bca bcb bcc bch bcn bco bcs bha bhb bhc bhh bho bhs bna bnb bnc bnn bno bns boa bob boc boh bon boo bos bsa bsb bsc bsh bsn bso bss c-- caa cab cac cah can cao cas cba cbb cbc cbh cbn cbo cbs cca ccb ccc cch ccn cco ccs ch- cha chb chc chh chn cho chs cn- cna cnb cnc cnh cnn cno cns co- coa cob coc coh con coo cos csa csb csc csh csn cso css haa hab hac hah han hao has hba hbb hbc hbh hbn hbo hbs hca hcb hcc hch hcn hco hcs hha hhb hhc hhh hhn hho hhs hna hnb hnc hnh hnn hno hns hoa hob hoc hoh hon hoo hos hsa hsb hsc hsh hsn hss naa nab nac nah nan nao nas nba nbb nbc nbn nbo nbs nca ncb ncc nch ncn nco ncs nha nhb nhc nhh nhn nhs nna nnb nnc nnh nnn nno nns no- noa nob noc noh non noo nos nsa nsb nsc nsh nsn nso nss oaa oab oac oah oan oao oas ob- oba obb obc obh obn obo obs oc- oca ocb occ och ocn oco ocs oha ohc ohh ohn oho ohs on- ona onb onc onh onn ono ons oo- ooa oob ooc ooh oon ooo oos os- osa osb osc osh osn oso oss saa sab sac sah san sao sas sba sbb sbc sbh sbn sbo sbs sca scb scc sch scn sco scs sh- sha shb shc shh shn sho shs sna snb snc snn sno sns soa sob soc soh son soo sos ss- ssa ssb ssc ssh ssn sso sss