-er bbb bbc bbe bbo bbq bbr bcb bcc bce bco bcq bcr be- beb bec bee beo beq ber bob boc boe boo boq bor bqc bqe brb bre bro brq brr c-- cbb cbc cbe cbo cbq cbr ccb ccc cce cco ccr ce- ceb cec cee ceo ceq cer co- cob coc coe coo coq cor cqb cqc cqo crb crc cre cro crq crr ebb ebc ebe ebo ebq ebr ec- ecb ecc ece eco ecq ecr eeb eec eee eeo eer eo- eob eoc eoe eoo eoq eor eqe eqq erb erc ere ero erq err ob- obb obc obe obo obr oc- ocb occ oco ocr oeb oec oee oeo oer oo- oob ooc ooo oor oqb oqo or- orb orc ore oro orr qbc qbe qbq qcc qco qec qee qeo qoo qor qqq qrb qrc qre rbb rbc rbe rbo rbr rcb rcc rce rco rcr re- reb rec ree reo req rer rob roc roe roo ror rqc rrb rrc rrq rrr