-er a-a a-b a-c aaa aab aac aae aag aar aau aav ab- aba abb abc abe abg abr abu abv ac- aca acb acc ace acg acr acu acv aea aeb aec aee aeg aer aeu aev ag- aga agb agc age agg agr agu agv ar- ara arb arc are arg arr aru arv au- aua aub auc aue aug aur auv av- ava avb avc ave avg avr avu b-u baa bab bac bae bag bar bau bav bba bbb bbc bbe bbg bbr bbu bca bcb bcc bce bcg bcr bcu bcv be- bea beb bec bee beg ber beu bev bga bgb bgc bge bgg bgr bgu bgv bra brb bre brg brr bru brv bua bub buc bue bug bur buu bva bvb bvc bve bvg bvr bvu bvv c-- caa cab cac cae cag car cau cav cba cbb cbc cbe cbg cbr cbu cbv cca ccb ccc cce ccg ccr ccu ccv ce- cea ceb cec cee ceg cer ceu cev cga cgb cgc cge cgg cgr cgu cgv cra crb crc cre crg crr cru crv cua cub cuc cue cug cur cuu cuv cva cvb cvc cve cvg cvr cvu cvv eaa eab eac eae eag ear eau eav eba ebb ebc ebe ebg ebr ebu ebv ec- eca ecb ecc ece ecg ecr ecu ecv eea eeb eec eee eeg eer eev ega egb egc ege egg egr egu era erb erc ere erg err eru erv eu- eua eub euc eue eug eur euv eva evb evc eve evg evr evv gaa gab gac gae gag gar gau gav gba gbc gbe gbg gbr gbu gbv gca gcb gcc gce gcg gcr gcu ge- gea geb gec gee geg ger geu gev gga ggb ggc ggg ggr ggu ggv gra grb grc gre grg grr gru grv gu- gua gub guc gue gug gur guu guv gva gvb gvc gve gvg gvr gvu ra- raa rab rac rae rag rar rau rav rba rbb rbc rbe rbg rbr rbu rca rcb rcc rce rcg rcr rcu rcv re- rea reb rec ree reg rer reu rev rga rgb rgc rge rgg rgr rgv rra rrb rrc rrg rrr rru rua rub ruc rue rug rur ruu ruv rva rvb rvc rve rvg rvr rvu rvv ua- uaa uab uac uae uag uar uau uav uba ubb ubc ube ubg ubr ubu ubv uca ucb ucc uce ucg ucr ucu ucv uea ueb uec uee ueg uer uga ugb ugc uge ugg ugr ugu ur- ura urb urc ure urg urr uru uua uuc uue uug uur uuu uva uvb uvc uve uvu uvv v-a v-e vaa vab vac vae vag var vau vav vba vbc vbg vbr vbv vca vcc vce vcr vcu vea veb vec vee veg ver veu vga vgc vgg vgr vgu vra vrb vrc vre vrg vrr vru vue vug vur vuv vva vvb vvc vvg vvr vvv