a-a a-b a-c aaa aab aac aad aah aao aar ab- aba abb abc abd abh abo abr ac- aca acb acc acd ach aco acr ad- ada adb adc add adh ado adr aha ahb ahc ahd ahh aho ahr aoa aob aoc aod aoh aoo aor ar- ara arb arc ard arh aro arr baa bab bac bad bah bao bar bba bbb bbc bbd bbh bbo bbr bca bcb bcc bcd bch bco bcr bda bdb bdc bdd bdh bdo bdr bha bhb bhc bhd bhh bho bhr boa bob boc bod boh boo bor bra brb brd brh bro brr c-- caa cab cac cad cah cao car cba cbb cbc cbd cbh cbo cbr cca ccb ccc ccd cch cco ccr cda cdb cdc cdd cdh cdo cdr ch- cha chb chc chd chh cho chr co- coa cob coc cod coh coo cor cra crb crc crd crh cro crr daa dab dac dad dah dao dar dba dbb dbc dbd dbh dbo dbr dca dcb dcc dcd dco dcr dda ddb ddc ddd ddh ddo ddr dh- dha dhb dhc dhd dhh dho dhr doa dob doc dod doh doo dor dra drb drc drd dro drr haa hab hac had hah hao har hba hbb hbc hbd hbh hbo hbr hca hcb hcc hcd hch hco hcr hda hdb hdc hdd hdh hdo hdr hha hhb hhc hhd hhh hho hhr hoa hob hoc hod hoh hoo hor hr- hra hrb hrc hrd hrh hro hrr oaa oab oac oad oah oao oar ob- oba obb obc obd obh obo obr oc- oca ocb occ ocd och oco ocr oda odb odc odd odh odo odr oha ohc ohd ohh oho ohr oo- ooa oob ooc ood ooh ooo oor or- ora orb orc ord orh oro orr ra- raa rab rac rad rah rao rar rba rbb rbc rbd rbh rbo rbr rca rcb rcc rcd rch rco rcr rda rdb rdc rdd rdh rdo rdr rh- rha rhb rhc rhd rhh rho rhr roa rob roc rod roh roo ror rra rrb rrc rrd rrh rrr