a-a a-b a-c aaa aab aac aad aao aar aas aau ab- aba abb abc abd abo abr abs abu ac- aca acb acc acd aco acr acs acu ad- ada adb adc add ado adr ads adu aoa aob aoc aod aoo aor aos aou ar- ara arb arc ard aro arr ars aru as- asa asb asc asd aso asr ass asu au- aua aub auc aud auo aur aus b-u baa bab bac bad bao bar bas bau bba bbb bbc bbd bbo bbr bbs bbu bca bcb bcc bcd bco bcr bcs bcu bda bdb bdc bdd bdo bdr bds bdu boa bob boc bod boo bor bos bou bra brb brd bro brr brs bru bsa bsb bsc bsd bso bsr bss bsu bua bub buc bud buo bur bus buu c-- caa cab cac cad cao car cas cau cba cbb cbc cbd cbo cbr cbs cbu cca ccb ccc ccd cco ccr ccs ccu cda cdb cdc cdd cdo cdr cds cdu co- coa cob coc cod coo cor cos cou cra crb crc crd cro crr crs cru csa csb csc csd cso csr css csu cua cub cuc cud cuo cur cus cuu daa dab dac dad dao dar das dau dba dbb dbc dbd dbo dbr dbs dbu dca dcb dcc dcd dco dcr dcs dcu dda ddb ddc ddd ddo ddr dds ddu doa dob doc dod doo dor dos dou dra drb drc drd dro drr drs dru dsa dsb dsc dsd dso dsr dss dsu dua dub duc dud duo dur dus oaa oab oac oad oao oar oas oau ob- oba obb obc obd obo obr obs obu oc- oca ocb occ ocd oco ocr ocs ocu oda odb odc odd odo odr ods odu oo- ooa oob ooc ood ooo oor oos or- ora orb orc ord oro orr ors oru os- osa osb osc osd oso osr oss osu ou- oua ouc oud ouo our ous ra- raa rab rac rad rao rar ras rau rba rbb rbc rbd rbo rbr rbs rbu rca rcb rcc rcd rco rcr rcs rcu rda rdb rdc rdd rdo rdr rds rdu roa rob roc rod roo ror ros rou rra rrb rrc rrd rrr rrs rru rsa rsb rsc rsd rso rsr rss rsu rua rub ruc rud ruo rur rus ruu saa sab sac sad sao sar sas sau sba sbb sbc sbd sbo sbr sbs sbu sca scb scc scd sco scr scs scu sda sdb sdc sdd sdo sdr sds sdu soa sob soc sod soo sor sos sou sr- sra srb src srd sro srr srs ss- ssa ssb ssc ssd sso ssr sss ssu sua sub suc sud suo sur sus suu ua- uaa uab uac uad uao uar uas uau uba ubb ubc ubo ubr ubs ubu uca ucb ucc ucd uco ucr ucs ucu uda udb udc udd udo udr uds udu uoa uob uoc uod uoo uor uos ur- ura urb urc urd uro urr urs uru usa usb usc usd uso usr uss usu uua uuc uur uus uuu