-er -ic a-a a-b a-c a-i aaa aab aac aae aai aak aao aap aar ab- aba abb abc abe abi abk abo abp abr ac- aca acb acc ace aci ack aco acp acr aea aeb aec aee aei aek aeo aep aer ai- aia aib aic aie aii aik aio aip air aka akb akc ake aki akk ako akp akr aoa aob aoc aoe aoi aok aoo aop aor ap- apa apb apc ape api apk apo app apr ar- ara arb arc are ari ark aro arp arr b-p baa bab bac bae bai bak bao bap bar bba bbb bbc bbe bbi bbk bbo bbp bbr bca bcb bcc bce bci bck bco bcp bcr be- bea beb bec bee bei bek beo bep ber bi- bia bib bic bie bii bik bio bip bir bka bkb bkc bke bkk bko bkp bkr boa bob boc boe boi bok boo bop bor bpa bpb bpc bpe bpi bpo bpp bpr bra brb bre bri brk bro brp brr c-- caa cab cac cae cai cak cao cap car cba cbb cbc cbe cbi cbk cbo cbp cbr cca ccb ccc cce cci cck cco ccp ccr ce- cea ceb cec cee cei cek ceo cep cer ci- cia cib cic cie cii cik cio cip cir cka ckb ckc cki cko co- coa cob coc coe coi cok coo cop cor cpa cpb cpc cpe cpi cpk cpo cpp cpr cra crb crc cre cri crk cro crp crr eaa eab eac eae eai eak eao eap ear eba ebb ebc ebe ebi ebk ebo ebp ebr ec- eca ecb ecc ece eci eck eco ecr eea eeb eec eee eek eeo eep eer eia eib eic eie eii eik eio eip eir eka ekb ekc eke eki eko ekp ekr eo- eoa eob eoc eoe eoi eok eoo eop eor ep- epa epb epc epe epi epo epp epr era erb erc ere eri erk ero erp err ia- iaa iab iac iae iai iao iap iar iba ibb ibc ibe ibi ibk ibo ibp ibr ica icb icc ice ici ick ico icp icr ie- iea iec iee iei iek iep ier iia iib iic iie iii iio iip iir ika ikb ikc ike iki ikk iko ikr io- ioa iob ioc ioe ioi ioo iop ior ipa ipb ipc ipe ipi ipo ipp ipr ir- ira irb irc ire iri irk iro irp irr ka- kaa kab kac kae kai kak kao kap kar kba kbb kbc kbe kbi kbk kbo kbp kbr kca kcb kcc kce kci kck kcp kcr ke- kea keb kec kee kei kek keo kep ker kia kib kic kie kii kik kio kip kir kkb kkc kke kki kkk kkp kkr koa kob koc koe koi kok koo kop kor kpa kpc kpe kpi kpk kpo kpp kpr kra krc kri krk kro krp krr o-i oaa oab oac oae oai oak oao oap oar ob- oba obb obc obe obi obk obo obp obr oc- oca ocb occ oci ock oco ocp ocr oea oeb oec oee oei oeo oep oer oia oib oic oie oii oik oio oip oir oka okb okc oke oki okk oko okp okr oo- ooa oob ooc ooi ook ooo oop oor op- opa opb opc ope opi opk opo opp opr or- ora orb orc ore ori ork oro orp orr p-p paa pab pac pae pai pak pao pap par pba pbb pbc pbe pbi pbk pbo pbp pbr pca pcb pcc pce pci pck pco pcp pcr pea peb pec pee pei pek peo pep per pia pib pic pie pii pik pio pip pir pka pkb pkc pke pki pko pkp pkr poa pob poc poe poi pok poo pop por ppa ppb ppc ppe ppi ppk ppo ppp ppr pra prb prc pre pri prk pro prp prr ra- raa rab rac rae rai rak rao rap rar rba rbb rbc rbe rbi rbk rbo rbp rbr rca rcb rcc rce rci rco rcp rcr re- rea reb rec ree rei rek reo rep rer ria rib ric rie rii rik rio rip rir rkb rkc rke rkk rko rkp roa rob roc roe roi rok roo rop ror rpa rpb rpc rpe rpi rpk rpo rpp rpr rra rrb rrc rri rrk rrp rrr