-er a-a a-c aaa aac aae aah aar aax ac- aca acc ace ach acr acx aea aec aee aeh aer aex aha ahc ahe ahh ahr ahx ar- ara arc are arh arr arx ax- axa axe axh axr axx c-- caa cac cae cah car cax cca ccc cce cch ccr ccx ce- cea cec cee ceh cer cex ch- cha chc che chh chr chx cra crc cre crh crr crx cxc cxh cxr cxx eaa eac eae eah ear eax ec- eca ecc ece ech ecr ecx eea eec eee eer eex eha ehc ehe ehh ehr era erc ere erh err ex- exa exc exe exh exr exx haa hac hae hah har hax hca hcc hce hch hcr he- hea hec hee heh her hex hha hhc hhe hhh hhr hr- hra hrc hre hrh hrr hxc ra- raa rac rae rah rar rax rca rcc rce rch rcr rcx re- rea rec ree reh rer rex rh- rha rhc rhe rhh rhr rra rrc rrh rrr rxr xaa xac xar xch xcr xcx xee xer xex xrc xrx xxx