-er a-a a-b a-c aaa aab aac aae aah aan aao aar ab- aba abb abc abe abh abn abo abr ac- aca acb acc ace ach acn aco acr aea aeb aec aee aeh aen aeo aer aha ahb ahc ahe ahh ahn aho ahr an- ana anb anc ane anh ann ano anr aoa aob aoc aoe aoh aon aoo aor ar- ara arb arc are arh arn aro arr baa bab bac bae bah ban bao bar bba bbb bbc bbe bbh bbn bbo bbr bca bcb bcc bce bch bcn bco bcr be- bea beb bec bee beh ben beo ber bha bhb bhc bhe bhh bho bhr bna bnb bnc bne bnn bno bnr boa bob boc boe boh bon boo bor bra brb bre brh brn bro brr c-- caa cab cac cae cah can cao car cba cbb cbc cbe cbh cbn cbo cbr cca ccb ccc cce cch ccn cco ccr ce- cea ceb cec cee ceh cen ceo cer ch- cha chb chc che chh chn cho chr cn- cna cnb cnc cne cnh cnn cno cnr co- coa cob coc coe coh con coo cor cra crb crc cre crh crn cro crr eaa eab eac eae eah ean eao ear eba ebb ebc ebe ebh ebn ebo ebr ec- eca ecb ecc ece ech ecn eco ecr eea eeb eec eee een eeo eer eha ehb ehc ehe ehh ehn eho ehr en- ena enb enc ene enh enn eno enr eo- eoa eob eoc eoe eoh eon eoo eor era erb erc ere erh ern ero err haa hab hac hae hah han hao har hba hbb hbc hbe hbh hbn hbo hbr hca hcb hcc hce hch hcn hco hcr he- hea heb hec hee heh hen heo her hha hhb hhc hhe hhh hhn hho hhr hna hnb hnc hne hnh hnn hno hoa hob hoc hoe hoh hon hoo hor hr- hra hrb hrc hre hrh hrn hro hrr naa nab nac nae nah nan nao nar nba nbb nbc nbe nbn nbo nbr nca ncb ncc nce nch ncn nco ncr ne- nea neb nec nee neh nen neo ner nha nhb nhc nhe nhh nhn nhr nna nnb nnc nne nnh nnn nno no- noa nob noc noe noh non noo nor nra nrb nrc nre nrn nro nrr oaa oab oac oae oah oan oao oar ob- oba obb obc obe obh obn obo obr oc- oca ocb occ och ocn oco ocr oea oeb oec oee oeh oen oeo oer oha ohc ohe ohh ohn oho ohr on- ona onb onc one onh onn ono onr oo- ooa oob ooc ooh oon ooo oor or- ora orb orc ore orh orn oro orr ra- raa rab rac rae rah ran rao rar rba rbb rbc rbe rbh rbn rbo rbr rca rcb rcc rce rch rcn rco rcr re- rea reb rec ree reh ren reo rer rh- rha rhb rhc rhe rhh rhn rho rhr rna rnb rnc rnh rnn rno rnr roa rob roc roe roh ron roo ror rra rrb rrc rrh rrn rrr