-th b-u bbb bbc bbh bbr bbt bbu bcb bcc bch bcr bct bcu bhb bhc bhh bhr bht bhu brb brh brr brt bru btb btc bth btr btt btu bub buc buh bur but buu c-- cbb cbc cbh cbr cbt cbu ccb ccc cch ccr cct ccu ch- chb chc chh chr cht chu crb crc crh crr crt cru ctb ctc cth ctr ctt ctu cub cuc cuh cur cut cuu hbb hbc hbh hbr hbt hbu hcb hcc hch hcr hct hhb hhc hhh hhr hht hhu hr- hrb hrc hrh hrr hrt hru htb htc hth htr htt hub huc huh hur hut huu rbb rbc rbh rbr rbt rbu rcb rcc rch rcr rct rcu rh- rhb rhc rhh rhr rht rhu rrb rrc rrh rrr rrt rru rtb rtc rtr rtt rtu rub ruc ruh rur rut ruu tbb tbc tbh tbr tbt tbu tcb tcc tch tcr tct tcu th- thb thc thh thr tht thu trb trc trh trr trt tru ttb ttc tth ttr ttt ttu tub tuc tuh tur tut tuu ubb ubc ubh ubr ubt ubu ucb ucc uch ucr uct ucu uhb uhc uhh uhr uht uhu ur- urb urc urr urt uru utb utc uth utr utt utu uuc uur uut uuu