a-a a-b a-c a-t aaa aab aac aao aar aat aau ab- aba abb abc abo abr abt abu ac- aca acb acc aco acr act acu aoa aob aoc aoo aor aot aou ar- ara arb arc aro arr art aru at- ata atb atc ato atr att atu au- aua aub auc auo aur aut b-u baa bab bac bao bar bat bau bba bbb bbc bbo bbr bbt bbu bca bcb bcc bco bcr bct bcu boa bob boc boo bor bot bou bra brb bro brr brt bru bta btb btc bto btr btt btu bua bub buc buo bur but buu c-- caa cab cac cao car cat cau cba cbb cbc cbo cbr cbt cbu cca ccb ccc cco ccr cct ccu co- coa cob coc coo cor cot cou cra crb crc cro crr crt cru cta ctb ctc cto ctr ctt ctu cua cub cuc cuo cur cut cuu oaa oab oac oao oar oat oau ob- oba obb obc obo obr obt obu oc- oca ocb occ oco ocr oct ocu oo- ooa oob ooc ooo oor oot or- ora orb orc oro orr ort oru ot- ota otb otc oto otr ott otu ou- oua ouc ouo our out ra- raa rab rac rao rar rat rau rba rbb rbc rbo rbr rbt rbu rca rcb rcc rco rcr rct rcu roa rob roc roo ror rot rou rra rrb rrc rrr rrt rru rta rtb rtc rto rtr rtt rtu rua rub ruc ruo rur rut ruu taa tab tac tao tar tat tau tba tbb tbc tbo tbr tbt tbu tca tcb tcc tco tcr tct tcu to- toa tob toc too tor tot tou tra trb trc tro trr trt tru tta ttb ttc tto ttr ttt ttu tua tub tuc tuo tur tut tuu ua- uaa uab uac uao uar uat uau uba ubb ubc ubo ubr ubt ubu uca ucb ucc uco ucr uct ucu uoa uob uoc uoo uor uot ur- ura urb urc uro urr urt uru uta utb utc uto utr utt utu uua uuc uur uut uuu