-er a-a a-b a-c aaa aab aac aae aao aap aar aav ab- aba abb abc abe abo abp abr abv ac- aca acb acc ace aco acp acr acv aea aeb aec aee aeo aep aer aev aoa aob aoc aoe aoo aop aor aov ap- apa apb apc ape apo app apr apv ar- ara arb arc are aro arp arr arv av- ava avb avc ave avo avp avr b-p baa bab bac bae bao bap bar bav bba bbb bbc bbe bbo bbp bbr bca bcb bcc bce bco bcp bcr bcv be- bea beb bec bee beo bep ber bev boa bob boc boe boo bop bor bov bpa bpb bpc bpe bpo bpp bpr bpv bra brb bre bro brp brr brv bva bvb bvc bve bvo bvp bvr bvv c-- caa cab cac cae cao cap car cav cba cbb cbc cbe cbo cbp cbr cbv cca ccb ccc cce cco ccp ccr ccv ce- cea ceb cec cee ceo cep cer cev co- coa cob coc coe coo cop cor cov cpa cpb cpc cpe cpo cpp cpr cpv cra crb crc cre cro crp crr crv cva cvb cvc cve cvo cvp cvr cvv eaa eab eac eae eao eap ear eav eba ebb ebc ebe ebo ebp ebr ebv ec- eca ecb ecc ece eco ecr ecv eea eeb eec eee eeo eep eer eev eo- eoa eob eoc eoe eoo eop eor ep- epa epb epc epe epo epp epr era erb erc ere ero erp err erv eva evb evc eve evo evp evr evv oaa oab oac oae oao oap oar oav ob- oba obb obc obe obo obp obr obv oc- oca ocb occ oco ocp ocr ocv oea oeb oec oee oeo oep oer oo- ooa oob ooc ooo oop oor oov op- opa opb opc ope opo opp opr opv or- ora orb orc ore oro orp orr orv ov- ova ovb ovc ove ovo ovp ovv p-p paa pab pac pae pao pap par pav pba pbb pbc pbe pbo pbp pbr pca pcb pcc pce pco pcp pcr pcv pea peb pec pee peo pep per pev poa pob poc poe poo pop por pov ppa ppb ppc ppe ppo ppp ppr ppv pra prb prc pre pro prp prr prv pva pvb pvc pve pvo pvp pvr pvv ra- raa rab rac rae rao rap rar rav rba rbb rbc rbe rbo rbp rbr rca rcb rcc rce rco rcp rcr rcv re- rea reb rec ree reo rep rer rev roa rob roc roe roo rop ror rov rpa rpb rpc rpe rpo rpp rpr rpv rra rrb rrc rrp rrr rva rvb rvc rve rvo rvp rvr rvv v-a v-e vaa vab vac vae vao vap var vav vba vbc vbo vbr vbv vca vcc vce vco vcp vcr vea veb vec vee veo vep ver voa vob voc voe voo vop vor vov vpa vpb vpc vpe vpo vpp vpr vra vrb vrc vre vrp vrr vva vvb vvc vvo vvr vvv