a-a a-b a-c aaa aab aac aae aag aau ab- aba abb abc abe abg abu ac- aca acb acc ace acg acu aea aeb aec aee aeg aeu ag- aga agb agc age agg agu au- aua aub auc aue aug b-u baa bab bac bae bag bau bba bbb bbc bbe bbg bbu bca bcb bcc bce bcg bcu be- bea beb bec bee beg beu bga bgb bgc bge bgg bgu bua bub buc bue bug buu c-- caa cab cac cae cag cau cba cbb cbc cbe cbg cbu cca ccb ccc cce ccg ccu ce- cea ceb cec cee ceg ceu cga cgb cgc cge cgg cgu cua cub cuc cue cug cuu eaa eab eac eae eag eau eba ebb ebc ebe ebg ebu ec- eca ecb ecc ece ecg ecu eea eeb eec eee eeg ega egb egc ege egg egu eu- eua eub euc eue eug gaa gab gac gae gag gau gba gbc gbe gbg gbu gca gcb gcc gce gcg gcu ge- gea geb gec gee geg geu gga ggb ggc ggg ggu gu- gua gub guc gue gug guu ua- uaa uab uac uae uag uau uba ubb ubc ube ubg ubu uca ucb ucc uce ucg ucu uea ueb uec uee ueg uga ugb ugc uge ugg ugu uua uuc uue uug uuu