-er b-p bbb bbc bbe bbh bbo bbp bbr bcb bcc bce bch bco bcp bcr be- beb bec bee beh beo bep ber bhb bhc bhe bhh bho bhp bhr bob boc boe boh boo bop bor bpb bpc bpe bph bpo bpp bpr brb bre brh bro brp brr c-- cbb cbc cbe cbh cbo cbp cbr ccb ccc cce cch cco ccp ccr ce- ceb cec cee ceh ceo cep cer ch- chb chc che chh cho chp chr co- cob coc coe coh coo cop cor cpb cpc cpe cph cpo cpp cpr crb crc cre crh cro crp crr ebb ebc ebe ebh ebo ebp ebr ec- ecb ecc ece ech eco ecr eeb eec eee eeo eep eer ehb ehc ehe ehh eho ehp ehr eo- eob eoc eoe eoh eoo eop eor ep- epb epc epe eph epo epp epr erb erc ere erh ero erp err hbb hbc hbe hbh hbo hbp hbr hcb hcc hce hch hco hcp hcr he- heb hec hee heh heo hep her hhb hhc hhe hhh hho hhp hhr hob hoc hoe hoh hoo hop hor hpb hpc hpe hph hpo hpp hpr hr- hrb hrc hre hrh hro hrp hrr ob- obb obc obe obh obo obp obr oc- ocb occ och oco ocp ocr oeb oec oee oeh oeo oep oer ohc ohe ohh oho ohp ohr oo- oob ooc ooh ooo oop oor op- opb opc ope oph opo opp opr or- orb orc ore orh oro orp orr p-p pbb pbc pbe pbo pbp pbr pcb pcc pce pch pco pcp pcr peb pec pee peh peo pep per phb phc phe pho php phr pob poc poe poh poo pop por ppb ppc ppe pph ppo ppp ppr prb prc pre prh pro prp prr rbb rbc rbe rbh rbo rbp rbr rcb rcc rce rch rco rcp rcr re- reb rec ree reh reo rep rer rh- rhb rhc rhe rhh rho rhp rhr rob roc roe roh roo rop ror rpb rpc rpe rph rpo rpp rpr rrb rrc rrh rrp rrr