-er a-a a-b a-c aaa aab aac aae aag aah aar ab- aba abb abc abe abg abh abr ac- aca acb acc ace acg ach acr aea aeb aec aee aeg aeh aer ag- aga agb agc age agg agh agr aha ahb ahc ahe ahg ahh ahr ar- ara arb arc are arg arh arr baa bab bac bae bag bah bar bba bbb bbc bbe bbg bbh bbr bca bcb bcc bce bcg bch bcr be- bea beb bec bee beg beh ber bga bgb bgc bge bgg bgh bgr bha bhb bhc bhe bhg bhh bhr bra brb bre brg brh brr c-- caa cab cac cae cag cah car cba cbb cbc cbe cbg cbh cbr cca ccb ccc cce ccg cch ccr ce- cea ceb cec cee ceg ceh cer cga cgb cgc cge cgg cgh cgr ch- cha chb chc che chg chh chr cra crb crc cre crg crh crr eaa eab eac eae eag eah ear eba ebb ebc ebe ebg ebh ebr ec- eca ecb ecc ece ecg ech ecr eea eeb eec eee eeg eer ega egb egc ege egg egh egr eha ehb ehc ehe ehg ehh ehr era erb erc ere erg erh err gaa gab gac gae gag gah gar gba gbc gbe gbg gbh gbr gca gcb gcc gce gcg gch gcr ge- gea geb gec gee geg geh ger gga ggb ggc ggg ggh ggr gha ghb ghc ghe ghg ghh ghr gra grb grc gre grg grh grr haa hab hac hae hag hah har hba hbb hbc hbe hbg hbh hbr hca hcb hcc hce hcg hch hcr he- hea heb hec hee heg heh her hga hgb hgc hge hgg hgh hgr hha hhb hhc hhe hhg hhh hhr hr- hra hrb hrc hre hrg hrh hrr ra- raa rab rac rae rag rah rar rba rbb rbc rbe rbg rbh rbr rca rcb rcc rce rcg rch rcr re- rea reb rec ree reg reh rer rga rgb rgc rge rgg rgh rgr rh- rha rhb rhc rhe rhg rhh rhr rra rrb rrc rrg rrh rrr