-er -up b-p b-u bbb bbc bbe bbp bbr bbu bcb bcc bce bcp bcr bcu be- beb bec bee bep ber beu bpb bpc bpe bpp bpr bpu brb bre brp brr bru bub buc bue bup bur buu c-- cbb cbc cbe cbp cbr cbu ccb ccc cce ccp ccr ccu ce- ceb cec cee cep cer ceu cpb cpc cpe cpp cpr cpu crb crc cre crp crr cru cub cuc cue cup cur cuu ebb ebc ebe ebp ebr ebu ec- ecb ecc ece ecr ecu eeb eec eee eep eer ep- epb epc epe epp epr epu erb erc ere erp err eru eu- eub euc eue eup eur p-p pbb pbc pbe pbp pbr pbu pcb pcc pce pcp pcr pcu peb pec pee pep per peu ppb ppc ppe ppp ppr ppu prb prc pre prp prr pru pub puc pue pup pur puu rbb rbc rbe rbp rbr rbu rcb rcc rce rcp rcr rcu re- reb rec ree rep rer reu rpb rpc rpe rpp rpr rpu rrb rrc rrp rrr rru rub ruc rue rup rur ruu ubb ubc ube ubp ubr ubu ucb ucc uce ucp ucr ucu ueb uec uee uep uer up- upb upc upe upp upr upu ur- urb urc ure urp urr uru uuc uue uur uuu