-er a-a a-b a-c aaa aab aac aae aag aao aar aav ab- aba abb abc abe abg abo abr abv ac- aca acb acc ace acg aco acr acv aea aeb aec aee aeg aeo aer aev ag- aga agb agc age agg ago agr agv aoa aob aoc aoe aog aoo aor aov ar- ara arb arc are arg aro arr arv av- ava avb avc ave avg avo avr baa bab bac bae bag bao bar bav bba bbb bbc bbe bbg bbo bbr bca bcb bcc bce bcg bco bcr bcv be- bea beb bec bee beg beo ber bev bga bgb bgc bge bgg bgo bgr bgv boa bob boc boe bog boo bor bov bra brb bre brg bro brr brv bva bvb bvc bve bvg bvo bvr bvv c-- caa cab cac cae cag cao car cav cba cbb cbc cbe cbg cbo cbr cbv cca ccb ccc cce ccg cco ccr ccv ce- cea ceb cec cee ceg ceo cer cev cga cgb cgc cge cgg cgo cgr cgv co- coa cob coc coe cog coo cor cov cra crb crc cre crg cro crr crv cva cvb cvc cve cvg cvo cvr cvv eaa eab eac eae eag eao ear eav eba ebb ebc ebe ebg ebo ebr ebv ec- eca ecb ecc ece ecg eco ecr ecv eea eeb eec eee eeg eeo eer eev ega egb egc ege egg ego egr eo- eoa eob eoc eoe eog eoo eor era erb erc ere erg ero err erv eva evb evc eve evg evo evr evv gaa gab gac gae gag gao gar gav gba gbc gbe gbg gbo gbr gbv gca gcb gcc gce gcg gco gcr ge- gea geb gec gee geg geo ger gev gga ggb ggc ggg ggo ggr ggv goa gob goc goe gog goo gor gov gra grb grc gre grg gro grr grv gva gvb gvc gve gvg gvo gvr oaa oab oac oae oag oao oar oav ob- oba obb obc obe obg obo obr obv oc- oca ocb occ ocg oco ocr ocv oea oeb oec oee oeg oeo oer oga ogc oge ogg ogo oo- ooa oob ooc oog ooo oor oov or- ora orb orc ore org oro orr orv ov- ova ovb ovc ove ovo ovv ra- raa rab rac rae rag rao rar rav rba rbb rbc rbe rbg rbo rbr rca rcb rcc rce rcg rco rcr rcv re- rea reb rec ree reg reo rer rev rga rgb rgc rge rgg rgo rgr rgv roa rob roc roe rog roo ror rov rra rrb rrc rrg rrr rva rvb rvc rve rvg rvo rvr rvv v-a v-e vaa vab vac vae vag vao var vav vba vbc vbg vbo vbr vbv vca vcc vce vco vcr vea veb vec vee veg veo ver vga vgc vgg vgo vgr voa vob voc voe vog voo vor vov vra vrb vrc vre vrg vrr vva vvb vvc vvg vvo vvr vvv