-er b-u bbb bbc bbe bbg bbr bbu bcb bcc bce bcg bcr bcu bcz be- beb bec bee beg ber beu bez bgb bgc bge bgg bgr bgu bgz brb bre brg brr bru brz bub buc bue bug bur buu buz bze bzr bzu bzz c-- cbb cbc cbe cbg cbr cbu cbz ccb ccc cce ccg ccr ccu ccz ce- ceb cec cee ceg cer ceu cez cgb cgc cge cgg cgr cgu crb crc cre crg crr cru crz cub cuc cue cug cur cuu cuz cz- czc cze ebb ebc ebe ebg ebr ebu ec- ecb ecc ece ecg ecr ecu eeb eec eee eeg eer egb egc ege egg egr egu erb erc ere erg err eru erz eu- eub euc eue eug eur eze ezr ezz gbc gbe gbg gbr gbu gbz gcb gcc gce gcg gcr gcu ge- geb gec gee geg ger geu gez ggb ggc ggg ggr ggu ggz grb grc gre grg grr gru gu- gub guc gue gug gur guu guz gzr gzu rbb rbc rbe rbg rbr rbu rcb rcc rce rcg rcr rcu re- reb rec ree reg rer reu rez rgb rgc rge rgg rgr rrb rrc rrg rrr rru rub ruc rue rug rur ruu ruz rzb rze ubb ubc ube ubg ubr ubu ucb ucc uce ucg ucr ucu ueb uec uee ueg uer ugb ugc uge ugg ugr ugu ur- urb urc ure urg urr uru urz uuc uue uug uur uuu uzb uzu z-g zbb zbc zbr zce zeb zec zee zer zez zgb zgg zub zuc zug zur zuz zzr zzz