a-a a-b a-c aaa aab aac aad aae aau ab- aba abb abc abd abe abu ac- aca acb acc acd ace acu ad- ada adb adc add ade adu aea aeb aec aed aee aeu au- aua aub auc aud aue b-u baa bab bac bad bae bau bba bbb bbc bbd bbe bbu bca bcb bcc bcd bce bcu bda bdb bdc bdd bde bdu be- bea beb bec bed bee beu bua bub buc bud bue buu c-- caa cab cac cad cae cau cba cbb cbc cbd cbe cbu cca ccb ccc ccd cce ccu cda cdb cdc cdd cde cdu ce- cea ceb cec ced cee ceu cua cub cuc cud cue cuu daa dab dac dad dae dau dba dbb dbc dbd dbe dbu dca dcb dcc dcd dce dcu dda ddb ddc ddd dde ddu de- dea deb dec ded dee deu dua dub duc dud due eaa eab eac ead eae eau eba ebb ebc ebd ebe ebu ec- eca ecb ecc ecd ece ecu ed- eda edb edc edd ede edu eea eeb eec eed eee eu- eua eub euc eud eue ua- uaa uab uac uad uae uau uba ubb ubc ube ubu uca ucb ucc ucd uce ucu uda udb udc udd ude udu uea ueb uec ued uee uua uuc uue uuu