a-a a-b a-c aaa aab aac aah aan aao aau ab- aba abb abc abh abn abo abu ac- aca acb acc ach acn aco acu aha ahb ahc ahh ahn aho ahu an- ana anb anc anh ann ano anu aoa aob aoc aoh aon aoo aou au- aua aub auc auh aun auo b-u baa bab bac bah ban bao bau bba bbb bbc bbh bbn bbo bbu bca bcb bcc bch bcn bco bcu bha bhb bhc bhh bho bhu bna bnb bnc bnn bno bnu boa bob boc boh bon boo bou bua bub buc buh bun buo buu c-- caa cab cac cah can cao cau cba cbb cbc cbh cbn cbo cbu cca ccb ccc cch ccn cco ccu ch- cha chb chc chh chn cho chu cn- cna cnb cnc cnh cnn cno cnu co- coa cob coc coh con coo cou cua cub cuc cuh cun cuo cuu haa hab hac hah han hao hau hba hbb hbc hbh hbn hbo hbu hca hcb hcc hch hcn hco hha hhb hhc hhh hhn hho hhu hna hnb hnc hnh hnn hno hnu hoa hob hoc hoh hon hoo hou hua hub huc huh hun huo huu naa nab nac nah nan nao nau nba nbb nbc nbn nbo nbu nca ncb ncc nch ncn nco ncu nha nhb nhc nhh nhn nhu nna nnb nnc nnh nnn nno nnu no- noa nob noc noh non noo nou nua nub nuc nuh nun nuo nuu oaa oab oac oah oan oao oau ob- oba obb obc obh obn obo obu oc- oca ocb occ och ocn oco ocu oha ohc ohh ohn oho ohu on- ona onb onc onh onn ono onu oo- ooa oob ooc ooh oon ooo ou- oua ouc ouh oun ouo ua- uaa uab uac uah uan uao uau uba ubb ubc ubh ubn ubo ubu uca ucb ucc uch ucn uco ucu uha uhb uhc uhh uho uhu un- una unb unc unh unn uno unu uoa uob uoc uon uoo uua uuc uun uuu