a-a a-b a-c aaa aab aac aae aan aao aau ab- aba abb abc abe abn abo abu ac- aca acb acc ace acn aco acu aea aeb aec aee aen aeo aeu an- ana anb anc ane ann ano anu aoa aob aoc aoe aon aoo aou au- aua aub auc aue aun auo b-u baa bab bac bae ban bao bau bba bbb bbc bbe bbn bbo bbu bca bcb bcc bce bcn bco bcu be- bea beb bec bee ben beo beu bna bnb bnc bne bnn bno bnu boa bob boc boe bon boo bou bua bub buc bue bun buo buu c-- caa cab cac cae can cao cau cba cbb cbc cbe cbn cbo cbu cca ccb ccc cce ccn cco ccu ce- cea ceb cec cee cen ceo ceu cn- cna cnb cnc cne cnn cno cnu co- coa cob coc coe con coo cou cua cub cuc cue cun cuo cuu eaa eab eac eae ean eao eau eba ebb ebc ebe ebn ebo ebu ec- eca ecb ecc ece ecn eco ecu eea eeb eec eee een eeo en- ena enb enc ene enn eno enu eo- eoa eob eoc eoe eon eoo eou eu- eua eub euc eue eun naa nab nac nae nan nao nau nba nbb nbc nbe nbn nbo nbu nca ncb ncc nce ncn nco ncu ne- nea neb nec nee nen neo neu nna nnb nnc nne nnn nno nnu no- noa nob noc noe non noo nou nua nub nuc nue nun nuo nuu oaa oab oac oae oan oao oau ob- oba obb obc obe obn obo obu oc- oca ocb occ ocn oco ocu oea oeb oec oee oen oeo on- ona onb onc one onn ono onu oo- ooa oob ooc oon ooo ou- oua ouc oue oun ouo ua- uaa uab uac uae uan uao uau uba ubb ubc ube ubn ubo ubu uca ucb ucc uce ucn uco ucu uea ueb uec uee uen un- una unb unc une unn uno unu uoa uob uoc uoe uon uoo uua uuc uue uun uuu