a-a a-b a-c aaa aab aac aae aao aau ab- aba abb abc abe abo abu ac- aca acb acc ace aco acu aea aeb aec aee aeo aeu aoa aob aoc aoe aoo aou au- aua aub auc aue auo b-u baa bab bac bae bao bau bba bbb bbc bbe bbo bbu bca bcb bcc bce bco bcu be- bea beb bec bee beo beu boa bob boc boe boo bou bua bub buc bue buo buu c-- caa cab cac cae cao cau cba cbb cbc cbe cbo cbu cca ccb ccc cce cco ccu ce- cea ceb cec cee ceo ceu co- coa cob coc coe coo cou cua cub cuc cue cuo cuu eaa eab eac eae eao eau eba ebb ebc ebe ebo ebu ec- eca ecb ecc ece eco ecu eea eeb eec eee eeo eo- eoa eob eoc eoe eoo eou eu- eua eub euc eue oaa oab oac oae oao oau ob- oba obb obc obe obo obu oc- oca ocb occ oco ocu oea oeb oec oee oeo oo- ooa oob ooc ooo ou- oua ouc oue ouo ua- uaa uab uac uae uao uau uba ubb ubc ube ubo ubu uca ucb ucc uce uco ucu uea ueb uec uee uoa uob uoc uoe uoo uua uuc uue uuu