a-a a-b a-c aaa aab aac aan aao aau aay ab- aba abb abc abn abo abu aby ac- aca acb acc acn aco acu acy an- ana anb anc ann ano anu any aoa aob aoc aon aoo aou au- aua aub auc aun auo ay- aya ayc ayn ayo ayu b-u baa bab bac ban bao bau bay bba bbb bbc bbn bbo bbu bby bca bcb bcc bcn bco bcu bcy bna bnb bnc bnn bno bnu boa bob boc bon boo bou boy bua bub buc bun buo buu buy by- bya byc byn byo byu c-- caa cab cac can cao cau cay cba cbb cbc cbn cbo cbu cby cca ccb ccc ccn cco ccu cn- cna cnb cnc cnn cno cnu cny co- coa cob coc con coo cou coy cua cub cuc cun cuo cuu cuy cya cyb cyc cyn cyo naa nab nac nan nao nau nay nba nbb nbc nbn nbo nbu nca ncb ncc ncn nco ncu nna nnb nnc nnn nno nnu no- noa nob noc non noo nou noy nua nub nuc nun nuo nuu nuy nya nyc nyn nyo nyu nyy oaa oab oac oan oao oau ob- oba obb obc obn obo obu oby oc- oca ocb occ ocn oco ocu on- ona onb onc onn ono onu ony oo- ooa oob ooc oon ooo ou- oua ouc oun ouo oya oyo ua- uaa uab uac uan uao uau uay uba ubb ubc ubn ubo ubu uby uca ucb ucc ucn uco ucu un- una unb unc unn uno unu uny uoa uob uoc uon uoo uua uuc uun uuu uyc uyo uyu yaa yab yac yan yao yau yay ybc yby yca ycc yco ycu ycy yna ynn ynu yny yob yoc yon yoo you yoy yua yun yuo yuu yuy yyb yyc yyu yyy