a-a a-b a-c a-t a-z aaa aab aac aao aat aau aaz ab- aba abb abc abo abt abu abz ac- aca acb acc aco act acu acz aoa aob aoc aoo aot aou at- ata atb atc ato att atu atz au- aua aub auc auo aut auz az- aza azb azo azt azu azz b-u baa bab bac bao bat bau baz bba bbb bbc bbo bbt bbu bca bcb bcc bco bct bcu bcz boa bob boc boo bot bou boz bta btb btc bto btt btu btz bua bub buc buo but buu buz bza bzo bzu bzz c-- caa cab cac cao cat cau caz cba cbb cbc cbo cbt cbu cbz cca ccb ccc cco cct ccu ccz co- coa cob coc coo cot cou coz cta ctb ctc cto ctt ctu ctz cua cub cuc cuo cut cuu cuz cz- czc czo czt oaa oab oac oao oat oau ob- oba obb obc obo obt obu oc- oca ocb occ oco oct ocu ocz oo- ooa oob ooc ooo oot ot- ota otb otc oto ott otu otz ou- oua ouc ouo out oza ozo ozt ozu ozz taa tab tac tao tat tau taz tba tbb tbc tbo tbt tbu tbz tca tcb tcc tco tct tcu to- toa tob toc too tot tou toz tta ttb ttc tto ttt ttu tua tub tuc tuo tut tuu tuz tza tzu ua- uaa uab uac uao uat uau uaz uba ubb ubc ubo ubt ubu uca ucb ucc uco uct ucu uoa uob uoc uoo uot uta utb utc uto utt utu utz uua uuc uut uuu uza uzb uzo uzu zaa zab zac zao zat zaz zbb zbc zbt zco zo- zoa zob zoc zoo zot zou zta zub zuc zut zuz zzt zzz