-er bbb bbc bbe bbh bbo bbr bcb bcc bce bch bco bcr be- beb bec bee beh beo ber bhb bhc bhe bhh bho bhr bob boc boe boh boo bor brb bre brh bro brr c-- cbb cbc cbe cbh cbo cbr ccb ccc cce cch cco ccr ce- ceb cec cee ceh ceo cer ch- chb chc che chh cho chr co- cob coc coe coh coo cor crb crc cre crh cro crr ebb ebc ebe ebh ebo ebr ec- ecb ecc ece ech eco ecr eeb eec eee eeo eer ehb ehc ehe ehh eho ehr eo- eob eoc eoe eoh eoo eor erb erc ere erh ero err hbb hbc hbe hbh hbo hbr hcb hcc hce hch hco hcr he- heb hec hee heh heo her hhb hhc hhe hhh hho hhr hob hoc hoe hoh hoo hor hr- hrb hrc hre hrh hro hrr ob- obb obc obe obh obo obr oc- ocb occ och oco ocr oeb oec oee oeh oeo oer ohc ohe ohh oho ohr oo- oob ooc ooh ooo oor or- orb orc ore orh oro orr rbb rbc rbe rbh rbo rbr rcb rcc rce rch rco rcr re- reb rec ree reh reo rer rh- rhb rhc rhe rhh rho rhr rob roc roe roh roo ror rrb rrc rrh rrr