a-a a-b a-c aaa aab aac aah aao aar aau ab- aba abb abc abh abo abr abu ac- aca acb acc ach aco acr acu aha ahb ahc ahh aho ahr ahu aoa aob aoc aoh aoo aor aou ar- ara arb arc arh aro arr aru au- aua aub auc auh auo aur b-u baa bab bac bah bao bar bau bba bbb bbc bbh bbo bbr bbu bca bcb bcc bch bco bcr bcu bha bhb bhc bhh bho bhr bhu boa bob boc boh boo bor bou bra brb brh bro brr bru bua bub buc buh buo bur buu c-- caa cab cac cah cao car cau cba cbb cbc cbh cbo cbr cbu cca ccb ccc cch cco ccr ccu ch- cha chb chc chh cho chr chu co- coa cob coc coh coo cor cou cra crb crc crh cro crr cru cua cub cuc cuh cuo cur cuu haa hab hac hah hao har hau hba hbb hbc hbh hbo hbr hbu hca hcb hcc hch hco hcr hha hhb hhc hhh hho hhr hhu hoa hob hoc hoh hoo hor hou hr- hra hrb hrc hrh hro hrr hru hua hub huc huh huo hur huu oaa oab oac oah oao oar oau ob- oba obb obc obh obo obr obu oc- oca ocb occ och oco ocr ocu oha ohc ohh oho ohr ohu oo- ooa oob ooc ooh ooo oor or- ora orb orc orh oro orr oru ou- oua ouc ouh ouo our ra- raa rab rac rah rao rar rau rba rbb rbc rbh rbo rbr rbu rca rcb rcc rch rco rcr rcu rh- rha rhb rhc rhh rho rhr rhu roa rob roc roh roo ror rou rra rrb rrc rrh rrr rru rua rub ruc ruh ruo rur ruu ua- uaa uab uac uah uao uar uau uba ubb ubc ubh ubo ubr ubu uca ucb ucc uch uco ucr ucu uha uhb uhc uhh uho uhr uhu uoa uob uoc uoo uor ur- ura urb urc uro urr uru uua uuc uur uuu