a-a a-b a-t aaa aab aao aar aas aat aau ab- aba abb abo abr abs abt abu aoa aob aoo aor aos aot aou ar- ara arb aro arr ars art aru as- asa asb aso asr ass ast asu at- ata atb ato atr ats att atu au- aua aub auo aur aus aut b-u baa bab bao bar bas bat bau bba bbb bbo bbr bbs bbt bbu boa bob boo bor bos bot bou bra brb bro brr brs brt bru bsa bsb bso bsr bss bst bsu bta btb bto btr bts btt btu bua bub buo bur bus but buu oaa oab oao oar oas oat oau ob- oba obb obo obr obs obt obu oo- ooa oob ooo oor oos oot or- ora orb oro orr ors ort oru os- osa osb oso osr oss ost osu ot- ota otb oto otr ots ott otu ou- oua ouo our ous out ra- raa rab rao rar ras rat rau rba rbb rbo rbr rbs rbt rbu roa rob roo ror ros rot rou rra rrb rrr rrs rrt rru rsa rsb rso rsr rss rst rsu rta rtb rto rtr rts rtt rtu rua rub ruo rur rus rut ruu saa sab sao sar sas sat sau sba sbb sbo sbr sbs sbt sbu soa sob soo sor sos sot sou sr- sra srb sro srr srs srt ss- ssa ssb sso ssr sss sst ssu sta stb sto str sts stt stu sua sub suo sur sus sut suu taa tab tao tar tas tat tau tba tbb tbo tbr tbs tbt tbu to- toa tob too tor tos tot tou tra trb tro trr trs trt tru tsa tsb tso tsr tss tst tsu tta ttb tto ttr tts ttt ttu tua tub tuo tur tus tut tuu ua- uaa uab uao uar uas uat uau uba ubb ubo ubr ubs ubt ubu uoa uob uoo uor uos uot ur- ura urb uro urr urs urt uru usa usb uso usr uss ust usu uta utb uto utr uts utt utu uua uur uus uut uuu