a-a a-b a-c aaa aab aac aam aau ab- aba abb abc abm abu ac- aca acb acc acm acu ama amb amc amm amu au- aua aub auc aum b-u baa bab bac bam bau bba bbb bbc bbm bbu bca bcb bcc bcm bcu bma bmb bmc bmm bmu bua bub buc bum buu c-- caa cab cac cam cau cba cbb cbc cbm cbu cca ccb ccc ccm ccu cma cmb cmc cmm cmu cua cub cuc cum cuu maa mab mac mam mau mba mbb mbc mbm mbu mc- mca mcb mcc mcm mcu mma mmb mmc mmm mmu mua mub muc mum muu ua- uaa uab uac uam uau uba ubb ubc ubu uca ucb ucc ucm ucu um- uma umb umc umm umu uua uuc uum uuu