-er a-a a-b a-c aaa aab aac aae aah aao aar aau ab- aba abb abc abe abh abo abr abu ac- aca acb acc ace ach aco acr acu aea aeb aec aee aeh aeo aer aeu aha ahb ahc ahe ahh aho ahr ahu aoa aob aoc aoe aoh aoo aor aou ar- ara arb arc are arh aro arr aru au- aua aub auc aue auh auo aur b-u baa bab bac bae bah bao bar bau bba bbb bbc bbe bbh bbo bbr bbu bca bcb bcc bce bch bco bcr bcu be- bea beb bec bee beh beo ber beu bha bhb bhc bhe bhh bho bhr bhu boa bob boc boe boh boo bor bou bra brb bre brh bro brr bru bua bub buc bue buh buo bur buu c-- caa cab cac cae cah cao car cau cba cbb cbc cbe cbh cbo cbr cbu cca ccb ccc cce cch cco ccr ccu ce- cea ceb cec cee ceh ceo cer ceu ch- cha chb chc che chh cho chr chu co- coa cob coc coe coh coo cor cou cra crb crc cre crh cro crr cru cua cub cuc cue cuh cuo cur cuu eaa eab eac eae eah eao ear eau eba ebb ebc ebe ebh ebo ebr ebu ec- eca ecb ecc ece ech eco ecr ecu eea eeb eec eee eeo eer eha ehb ehc ehe ehh eho ehr ehu eo- eoa eob eoc eoe eoh eoo eor eou era erb erc ere erh ero err eru eu- eua eub euc eue eur haa hab hac hae hah hao har hau hba hbb hbc hbe hbh hbo hbr hbu hca hcb hcc hce hch hco hcr he- hea heb hec hee heh heo her heu hha hhb hhc hhe hhh hho hhr hhu hoa hob hoc hoe hoh hoo hor hou hr- hra hrb hrc hre hrh hro hrr hru hua hub huc hue huh huo hur huu oaa oab oac oae oah oao oar oau ob- oba obb obc obe obh obo obr obu oc- oca ocb occ och oco ocr ocu oea oeb oec oee oeh oeo oer oha ohc ohe ohh oho ohr ohu oo- ooa oob ooc ooh ooo oor or- ora orb orc ore orh oro orr oru ou- oua ouc oue ouh ouo our ra- raa rab rac rae rah rao rar rau rba rbb rbc rbe rbh rbo rbr rbu rca rcb rcc rce rch rco rcr rcu re- rea reb rec ree reh reo rer reu rh- rha rhb rhc rhe rhh rho rhr rhu roa rob roc roe roh roo ror rou rra rrb rrc rrh rrr rru rua rub ruc rue ruh ruo rur ruu ua- uaa uab uac uae uah uao uar uau uba ubb ubc ube ubh ubo ubr ubu uca ucb ucc uce uch uco ucr ucu uea ueb uec uee ueh uer uha uhb uhc uhe uhh uho uhr uhu uoa uob uoc uoe uoo uor ur- ura urb urc ure uro urr uru uua uuc uue uur uuu