a-a a-b a-c a-t aaa aab aac aak aar aat aau ab- aba abb abc abk abr abt abu ac- aca acb acc ack acr act acu aka akb akc akk akr aku ar- ara arb arc ark arr art aru at- ata atb atc atr att atu au- aua aub auc auk aur aut b-u baa bab bac bak bar bat bau bba bbb bbc bbk bbr bbt bbu bca bcb bcc bck bcr bct bcu bka bkb bkc bkk bkr bkt bra brb brk brr brt bru bta btb btc btk btr btt btu bua bub buc buk bur but buu c-- caa cab cac cak car cat cau cba cbb cbc cbk cbr cbt cbu cca ccb ccc cck ccr cct ccu cka ckb ckc ckt cra crb crc crk crr crt cru cta ctb ctc ctk ctr ctt ctu cua cub cuc cuk cur cut cuu k-t ka- kaa kab kac kak kar kat kau kba kbb kbc kbk kbr kbu kca kcb kcc kck kcr kct kcu kkb kkc kkk kkr kkt kku kra krc krk krr krt kru kta ktb ktc ktk ktr ktt ktu kub kuc kuk kur kut kuu ra- raa rab rac rak rar rat rau rba rbb rbc rbk rbr rbt rbu rca rcb rcc rcr rct rcu rkb rkc rkk rkt rku rra rrb rrc rrk rrr rrt rru rta rtb rtc rtk rtr rtt rtu rua rub ruc ruk rur rut ruu taa tab tac tak tar tat tau tba tbb tbc tbk tbr tbt tbu tca tcb tcc tck tcr tct tcu tka tkb tkc tkk tkr tkt tra trb trc trk trr trt tru tta ttb ttc ttk ttr ttt ttu tua tub tuc tuk tur tut tuu ua- uaa uab uac uak uar uat uau uba ubb ubc ubk ubr ubt ubu uca ucb ucc uck ucr uct ucu uka ukb ukc ukk ukr uku ur- ura urb urc urk urr urt uru uta utb utc utk utr utt utu uua uuc uur uut uuu