a-a a-b a-c aaa aab aac aad aao aar aav ab- aba abb abc abd abo abr abv ac- aca acb acc acd aco acr acv ad- ada adb adc add ado adr adv aoa aob aoc aod aoo aor aov ar- ara arb arc ard aro arr arv av- ava avb avc avd avo avr baa bab bac bad bao bar bav bba bbb bbc bbd bbo bbr bca bcb bcc bcd bco bcr bcv bda bdb bdc bdd bdo bdr bdv boa bob boc bod boo bor bov bra brb brd bro brr brv bva bvb bvc bvd bvo bvr bvv c-- caa cab cac cad cao car cav cba cbb cbc cbd cbo cbr cbv cca ccb ccc ccd cco ccr ccv cda cdb cdc cdd cdo cdr cdv co- coa cob coc cod coo cor cov cra crb crc crd cro crr crv cva cvb cvc cvd cvo cvr cvv daa dab dac dad dao dar dav dba dbb dbc dbd dbo dbr dbv dca dcb dcc dcd dco dcr dcv dda ddb ddc ddd ddo ddr doa dob doc dod doo dor dov dra drb drc drd dro drr drv dva dvb dvc dvd dvr oaa oab oac oad oao oar oav ob- oba obb obc obd obo obr obv oc- oca ocb occ ocd oco ocr ocv oda odb odc odd odo odr odv oo- ooa oob ooc ood ooo oor oov or- ora orb orc ord oro orr orv ov- ova ovb ovc ovd ovo ovv ra- raa rab rac rad rao rar rav rba rbb rbc rbd rbo rbr rca rcb rcc rcd rco rcr rcv rda rdb rdc rdd rdo rdr rdv roa rob roc rod roo ror rov rra rrb rrc rrd rrr rva rvb rvc rvd rvo rvr rvv v-a vaa vab vac vad vao var vav vba vbc vbd vbo vbr vbv vca vcc vcd vco vcr vdb vdc vdd vdo vdr vdv voa vob voc vod voo vor vov vra vrb vrc vrd vrr vva vvb vvc vvo vvr vvv