-er b-u bbb bbc bbe bbr bbs bbu bcb bcc bce bcr bcs bcu bcz be- beb bec bee ber bes beu bez brb bre brr brs bru brz bsb bsc bse bsr bss bsu bub buc bue bur bus buu buz bze bzr bzs bzu bzz c-- cbb cbc cbe cbr cbs cbu cbz ccb ccc cce ccr ccs ccu ccz ce- ceb cec cee cer ces ceu cez crb crc cre crr crs cru crz csb csc cse csr css csu csz cub cuc cue cur cus cuu cuz cz- czc cze ebb ebc ebe ebr ebs ebu ec- ecb ecc ece ecr ecs ecu eeb eec eee eer ees erb erc ere err ers eru erz es- esb esc ese esr ess esu eu- eub euc eue eur eus eze ezr ezs ezz rbb rbc rbe rbr rbs rbu rcb rcc rce rcr rcs rcu re- reb rec ree rer res reu rez rrb rrc rrr rrs rru rsb rsc rse rsr rss rsu rub ruc rue rur rus ruu ruz rzb rze sbb sbc sbe sbr sbs sbu scb scc sce scr scs scu se- seb sec see ser ses seu sez sr- srb src sre srr srs ss- ssb ssc sse ssr sss ssu ssz sub suc sue sur sus suu suz sze szr szu ubb ubc ube ubr ubs ubu ucb ucc uce ucr ucs ucu ueb uec uee uer ues ur- urb urc ure urr urs uru urz usb usc use usr uss usu usz uuc uue uur uus uuu uzb uzu zbb zbc zbr zbs zce zcs zeb zec zee zer zes zez zrs zse zsu zsz zub zuc zur zus zuz zzr zzs zzz